Dr Andrew F. Rich

Oral squamous cell carcinomas (OSCCs) are commonly diagnosed in animals, particularly African pygmy hedgehogs (Atelerix albiventris) (APHs). This study reviews individual hedgehog and tumor characteristics of 17 OSCCs in APHs, as well as 94 OSCC cases currently recorded in the scientific literature, to assess common trends and potential risk factors for these neoplasms in the species. A single detailed case of OSCC is described in the case series; it was submitted for autopsy with cytological and diagnostic imaging data while the remaining cases were routine histological biopsies. Histologically, OSCCs showed infiltrative trabeculae and nests of squamous epithelial cells with variable degrees of keratinization. Bone and nasal invasion were observed in some OSCCs (n = 3), consistent with the literature. Metastasis has been rarely reported and was not recorded in this case series. Inflammation was observed in examined OSCCs, as well as in literature cases, including in the mucosa adjacent to OSCCs, suggesting a potential role of chronic inflammation in tumor promotion. This study highlights that individuals older than 2 years old with chronic stomatitis are potentially at higher risk of developing OSCCs, with the maxilla (66.0%) being the most common site of tumor development. No sex predilection is evident. Recurrence and metastatic potential remain insufficiently documented, warranting further investigation.

Neoplasms are rarely reported in Phoenicopteriformes, though malignancies are often diagnosed through postmortem examinations. Two captive Chilean flamingos (Phoenicopterus chilensis) were presented with lesions of relatively innocuous appearance. Case 1, a 40-year-old female, had a perinasal maxillary tomium lesion (10 × 5 × 5 mm). Fine-needle aspirate cytology suggested a poorly differentiated malignant neoplasm, with an incisional biopsy, histopathology, and immunohistochemistry confirming malignant melanoma. Unexpected regression occurred over 4.5 months, during which multifocal pulmonary nodules were detected on computed tomography. The bird died 8 months following the initial presentation. Necropsy revealed hemocoelom, hepatic hemorrhagic lesions (≤50 mm), and smaller, cream-colored, firm pulmonary and renal nodules (1–18 mm). Whole-body radiography and histopathology confirmed a diagnosis of intracoelomic extraskeletal giant cell-rich osteosarcoma (with telangiectatic features) affecting the liver, kidneys, and lungs, with no primary osseous origin identified. Melanoma was not identified on gross or histopathologic examination of tissues submitted from this flamingo. Case 2, a 53-year-old female, was presented for right limb lameness and 2 proliferative lesions on the dorsal and lateral aspects of the right metatarsophalangeal joint. Incisional biopsy and histopathology of the dorsal lesion revealed hyperplastic, necrotizing, and heterophilic dermatitis. These dermal lesions resolved with medical management. Fourteen months after the lesions healed, the bird developed right leg paresis and an 8-mm lesion at the same site as the previous lateral lesion. Owing to suspected renal disease causing the paresis, euthanasia was performed. Necropsy revealed multifocal renal lesions with secondary sciatic nerve involvement. Histopathology and immunohistochemistry confirmed a diagnosis of cutaneous malignant melanoma with renal metastases. This report documents 2 novel cases of cutaneous malignant melanoma in Chilean flamingos, with differing clinical outcomes, and intracoelomic extraskeletal osteosarcoma.

Given the limited ocular pathology data for common cuttlefish Sepia officinalis and hummingbird bobtail squid Euprymna berryi despite their high visual dependency, the purpose of this study was to investigate and describe the ophthalmic lesions in a cohort of laboratory-housed common cuttlefish and hummingbird bobtail squid. Cases were retrospectively selected from the International Zoo Veterinary Group Pathology database that reported confirmed clinical ophthalmic lesions or histopathological lesions. Twenty-five cases were identified that included clinical records and gross and histopathological examination of whole specimens. The cases included 19 common cuttlefish and six hummingbird bobtail squid, thus providing a sample of 50 eyes and orbital cavities. Thirty-two of 50 individual eyes (64%) and 30 of 50 white bodies (60%) were affected. The most frequent lesion that was observed was inflammation (n = 29/32, 91%), primarily manifesting as uveitis (n = 23/32, 72%) and phakitis (n = 10/32, 31%). Cataracts were also common (n = 14/32, 44%), often with cataract-associated inflammation (n = 9/14, 64%). Leukopoietic hyperplasia of the white body was bilaterally observed in 15 of 25 animals (60%) and was thought to be associated with exophthalmos. In the absence of notable intraocular or infraorbital lesions in some animals, this change was considered reactive, likely in response to nonocular lesions, such as ulcerative dermatitis and branchitis. Notable additional findings included hypopyon-like lesions (n = 3/32, 9%), a single case of congenital ocular malformation, and one case with mesenchymal proliferations that were reminiscent of florid fibroplasia. This study contributes to the expanding knowledge of cephalopod ocular pathology, with previously unreported findings in these cephalopods including congenital ocular malformation and cases of ­hypopyon-like lesions with proteinaceous material exudation and hemocytes in the anterior chamber. Additionally, it offers specific insights into the ocular pathology of the hummingbird bobtail squid.

This study investigates a potential association between an unusual presentation of pulmonary arterial atherosclerosis in meerkats and parasitism by Angiostrongylus vasorum, a cardiopulmonary nematode known to induce pulmonary arteritis and pneumonia in domestic dogs and foxes. A retrospective analysis of 226 meerkats that underwent postmortem examination was performed, reviewing gross (n = 226) or microscopic (n = 201) records or both from the International Zoo Veterinary Group Pathology and the Zoological Society of London between January 2003 to May 2023. These records combined with additional PCR testing identified 19 cases consistent with angiostrongylosis, in which the infection was attributed as the cause of death in 11 of 19 (59%). PCR and amplicon sequencing of the NAD3 locus of an adult nematode recovered from the heart of one animal, and of frozen lung tissue from another five animals, showed 100% identity with A. vasorum. Formalin-fixed paraffin-embedded lungs were available for 18 of 19 cases of angiostrongylosis enabling description of histopathologic features. The most common finding was granulomatous interstitial pneumonia (18 of 18), followed by arterial medial hyperplasia (16 of 18), arterial intimal hyperplasia or fibrosis (13 of 18), arteritis (11 of 18), interstitial fibrosis (9 of 18), thrombosis (7 of 18), and pulmonary arterial atherosclerosis (7 of 18). Pulmonary arterial atherosclerosis was described in only 2% (3 of 183) of nonparasitized animals, indicating a strong association between pulmonary arterial atherosclerosis and angiostrongylosis (odds ratio 36.3; P < 0.001). Where available, history of serum cholesterol concentration was obtained (n = 25) to investigate whether hypercholesterolemia, a common finding in captive meerkats that are fed inappropriate diets, is also a contributing factor to this phenomenon. Higher levels were associated with another cholesterol-related disease, cholesterol granulomas (P = 0.029), but not with pulmonary arterial atherosclerosis (P = 0.81). Angiostrongylosis is an important cause of mortality in captive meerkats in the United Kingdom and a risk factor for pulmonary arterial atherosclerosis.

A stranded juvenile harbor seal (Phoca vitulina) was necropsied following acute dyspnea and death. Necropsy revealed an esophageal perforation caused by fourth-stage Contracaecum osculatum larvae with Streptococcus phocae–associated pyothorax and aspiration pneumonia. Pyothorax is uncommon in seals, and S. phocae is considered a novel etiology, secondary to verminous esophageal perforation.

Coccidiosis is the most prevalent disease in octopuses under human care; however, detailed macroscopic and histological examinations illustrating its hallmark features are scarce. This report presents a classic case of severe coccidiosis in an aquarium-derived formalin-fixed common octopus (Octopus vulgaris) as an educational resource for veterinarians working in aquatic medicine.

Cholelithiasis is a rarely reported condition in lions and zoological carnivora. This report documents two geriatric, male, African lions (Panthera leo; Lions A and B) submitted for routine necropsy following euthanasia due to unrelated conditions. Pre-euthanasia serum biochemistry revealed unremarkable hepatobiliary markers for both lions. On necropsy, cholelithiasis was observed in both individuals, with Lion A displaying more severe gallstone accumulation and a biliary cystadenoma. Gallstones from Lion A were analysed using X-ray diffraction, element content analysis, and scanning electron microscopy. Findings revealed that the black appearance of the choleliths, the absence of acicular cholesterol, and minimal calcium content (1.05%) were consistent with bilirubin polymer composition. Risk factors for cholelithiasis in these lions may have included geriatric age, sex (male), good body condition, and chronic biliary tract inflammation. This case report presents the first documented instances of incidental cholelithiasis in African lions, providing novel findings into its composition (bilirubin polymers), possible risk factors, and histopathological features.

The white-winged duck (Asarcornis scutulata) is an endangered large, stocky anatid species that originates from South-East Asia. We report an adult, 9-year-old male specimen that presented with a 7-month history of intermittent lethargy and pale mucous membranes. Haematology and plasma biochemistry analyses, performed twice at a 6-week interval, revealed anaemia, lymphocytosis and raised renal and hepatic enzyme activities. These findings initially raised clinical suspicion of either avian tuberculosis (ATB), amyloidosis or neoplasia based on species predilection. Initial blood smear evaluation revealed occasional atypical lymphocytes. The duck slowly lost weight over 8 weeks, despite appearing behaviourally normal, prior to rapid deterioration (ie, lethargy and incoordination) resulting in death before euthanasia could be performed. On post-mortem examination, the bird was in poor body condition, with visceral lesions including hydropericardium, an opaquely thickened pericardium, hepatomegaly with dark-to-pale tan capsular and parenchymal mottling, and splenomegaly. On histology and immunohistochemistry, extensive T-cell lymphocytic infiltration was found throughout the pericardium, liver and spleen, with segmental infiltrates within the kidneys and small intestine. Intravascular neoplastic T cells were also seen in large numbers throughout the vascular lumina of the affected organs (indicative of metastatic dissemination). A disseminated lymphoma was favoured over a primary lymphocytic leukaemia due to the lack of lymphocytosis on haematology. This is the first report of disseminated T-cell lymphoma in this endangered duck species.

A geriatric, 16-year-9-month-old, male snow leopard (Panthera uncia) under human care was necropsied after euthanasia over concerns for worsening chronic kidney disease and bilateral blindness. Gross and histological examinations revealed necrotising frontal sinusitis and osteomyelitis with mixed-cellular rhinotracheitis, affecting the right frontal sinus, right nasal cavity and trachea, respectively, with intralesional and cilia-associated Gram-negative bacilli detected. Microbiological cultures were inconclusive, although Bordetella bronchiseptica and feline herpesvirus 1 were positive on PCR analysis. Immunohistochemistry, however, refuted active feline herpesvirus 1 involvement. Marked, chronic, bilateral, renal degeneration and fibrosis (chronic kidney disease), mild hepatic cirrhosis, bilateral chronic degenerative stifle joint disease and testicular intratubular seminoma were also detected on postmortem examination. No gross ocular or optic nerve lesions were identified; however, histology indicated bilateral diffuse outer retinal atrophy and retinal detachment, supportive of clinical blindness at time of death. This case represents the first report of chronic rhinosinusitis and osteomyelitis in a snow leopard.

White-tailed antsangies (Brachytarsomys albicauda) are Madagascan rodents uncommonly kept in captivity. Hymenolepis nana is a cestode with an unusual life cycle, incorporating direct, indirect and autoinfective stages. This case series represents the first reported outbreak of H. nana cestodiasis in white-tailed antsangies, summarizing macroscopic and histological findings in four cases. On post-mortem examination (PME), numerous cysticerci were detected consistently throughout the intestinal serosa, liver, mesenteric lymphatic vasculature and mesenteric lymph nodes. Pancreatic cysticerci were observed in one case. Adult tapeworms, larvae and eggs were found only in the small intestine, and faecal egg shedding was a feature. Histopathological examination identified adult, larval and encysted cestodes within the respective gross lesions, with pulmonary, pancreatic and splenic involvement detected in a single case. The cestodes sampled on PME were identified by polymerase chain reaction and DNA sequencing, with H. nana confirmed in all cases. Visceral larva migrans was consistent throughout all specimens, in contrast with the natural infections of standard rodent hosts, and may be considered a likely pathological feature of H. nana infection in white-tailed antsangies.

Ulcerative dermatitis (UD) is common in ornamental fish collections and is typically associated with a wide range of bacterial aetiologies. Clinical reports describing Shewanella xiamenensis-associated UD are limited, however, despite growing attention to pathogenic Shewanella species in fish. Two out of 95 koi carp with UD were presented for clinical assessment by a commercial collection (n = 3000 fish) and subsequently killed on welfare grounds for necropsy. Both specimens exhibited extensive cutaneous ulcers and coelomic fat necrosis with petechial haemorrhages on post-mortem examination. Shewanella xiamenensis was cultured from ulcerated skin tissues taken from both fish, with consistent intralesional gram-negative rod-like bacteria seen on skin scrape cytology. Histology also confirmed intralesional gram-negative rod-like bacteria within multiple ulcerative and erosive dermatitis lesions, plus myofibre necrosis and necrotising coelomic steatitis, in both specimens. Features associated with impaired generalised osmoregulation secondary to UD were detected within the striated muscle underlying the ulcers, the gills, and the caudal aspects of the kidneys. Additional histological features suggestive of sepsis were also seen in one of the fish. In the interim period, morbidity had increased from 3.2% to around 30% of the entire stock. Following culture results, increased pond water changes were implemented (q.2-3d) and the remaining stock was treated with florfenicol, resulting in complete resolution of UD in the collection (as per client). This article highlights the first description of S. xiamenensis-associated UD in koi carp/diseased ornamental fish in the United Kingdom.

Oral cavity squamous cell carcinomas (OCSCCs) are relatively common in multiple non-human primate species but are poorly documented in Goeldi's monkeys. Four Goeldi's monkeys with OCSCC, from three zoological collections, underwent necropsy with cytology, histopathology, immunohistochemistry, and pan-herpesvirus PCR analysis. All animals were euthanised and exhibited poor-to-emaciated body condition. Three OCSCCs arose from the maxillary oral mucosa and a single OCSCC was primarily mandibular, with bone invasion evident in three cases. Histologically, one OCSCC in situ was diagnosed, whilst the rest were typically invasive OCSCCs. Neoplastic cells were immunopositive for pancytokeratin and E-cadherin. All examined cases were negative for regional lymph node (RLN) and/or distant metastases, cyclooxygenase-2 (COX-2) immunoexpression, and panherpesvirus PCR expression. OCSCCs in Goeldi's monkeys may be deeply invasive, but not readily metastatic. No herpesvirus-association or COX-2 expression was evident; the latter suggesting that NSAIDs are unlikely to be a viable chemotherapeutic treatment.

This retrospective study examines pathologic findings in 593 captive cephalopods (340 octopuses, 130 cuttlefish, 33 squid, and 90 nautiluses; 22 species in total) submitted to International Zoo Veterinary Group Pathology between May 2003 and August 2022. Common octopus, European common cuttlefish, hummingbird bobtail squid, and chambered nautilus were the most numerous species from the included orders of Octopoda, Sepiida, Sepiolida, and Nautilida, respectively. Commonly identified conditions included coccidiosis and renal dicyemid mesozoan infection in octopuses, amebiasis in squid, bacterial infections in cuttlefish, and idiopathic multisystemic inflammatory disease in nautiluses. Coccidiosis was most frequent in common octopuses, giant Pacific octopuses, and California 2-spot octopuses (present in 68.4%, 46.3%, and 23.8% of these species, respectively) and was the attributed cause of death in 32.3%, 36.0%, and 60.0% of such cases, respectively. Ulcerative dermatitis (UD) was common, affecting squid, cuttlefish, and octopuses, while many nautiluses exhibited black shell disease and/or UD. Notable differences in the prevalence of UD were detected between laboratory and aquaria-housed decapodiforms; 52.2% for laboratory squid versus 20.0% in aquaria; 51.3% in laboratory cuttlefish versus 11.0% in aquaria. All octopuses and nautiluses in the study were derived from aquaria. Semelparity-associated death in Coleoidea species was identified in 22.4% of octopuses, 11.5% of cuttlefish, and 6.1% of squid. This report aims to provide an overview and reassessment of species-specific disease patterns under aquarium and laboratory management as a starting point for future developments in husbandry and disease investigation.

A 4-year-old, male Rothschild's giraffe presented with a rapidly growing, hemispherical, approximately 40 × 20 × 20 mm, raised, firm mass located on the mid-region of the left lateral thigh. Complete surgical excision (minimal 20 mm margins in all orientations) was achieved under behavioural restraint and local anaesthesia. Cytology and histopathology diagnosed a poorly differentiated malignant mesenchymal neoplasm, with nuclear karyomegaly, multinucleation and atypical horseshoe-like forms. The neoplastic cells exhibited diffuse strong cytoplasmic immunopositivity to vimentin, and were negative to smooth muscle actin, desmin, glial fibrillary acidic protein, and CD18 immunomarkers, giving a diagnosis of undifferentiated pleomorphic sarcoma. At 1 year follow-up, the giraffe is clinically well with no health issues after complete excision, and no evidence of local recurrence or distant metastases, based on physical examination and routine haematology/biochemistry. To the authors’ knowledge, this is the first report of an undifferentiated pleomorphic sarcoma (atypical fibroxanthoma-subtype) in a giraffe.

A 4-year-old, male, neutered pug was referred for brachycephalic obstructive airway syndrome evaluation. The patient had a history of exercise and warm weather intolerance, causing chronic clinical signs of nasal discharge and reverse sneezing. A computed tomography scan revealed an unerupted tooth within the left nasal cavity and rostral left nasal meatus with an associated cystic lesion, extending to the right side, causing complete obstruction of the nasal passage. The left maxillary canine tooth (204) was surgically extracted, and the surrounding cystic lining was extirpated. Histopathology identified the structure as a dentigerous cyst, with complete tissue margins, supporting a reduced likelihood of local recurrence. After 7 months, the patient had significantly improved and had no further episodes of nasal discharge.

An adult, female degu (Octodon degus) presented with a single, firm, nodular, 8 × 8 × 10 mm, fast-growing mass located between the cranial thoracic vertebrae and the cranial aspect of the right scapula. Cytology, histopathology and immunohistochemistry confirmed an extra-adrenal paraganglioma (chromogranin A, neuron-specific enolase and S100 positive, and cytokeratin AE1/3 negative) within the deep adipose tissue underlying the panniculus muscle. Complete surgical excision was achieved; however, within 1 month after surgery, a novel fast-growing intra-abdominal mass was detected. The animal was subsequently euthanased. Postmortem examination only revealed a single, well-demarcated, spherical, firm, 40 × 40 × 42 mm tumour arising from within the left uterine horn. Histology and immunohistochemistry confirmed a uterine leiomyosarcoma (smooth muscle actin positive). This case report represents the first case of an extra-adrenal paraganglioma and the second case of a uterine-specific leiomyosarcoma in this species.

Although the equine sarcoid is the most common skin neoplasm in domesticated horses, histopathological characteristics have not previously been evaluated for association with recurrence. The aim of this retrospective cohort study was to investigate clinical and histopathological features of excised equine sarcoids and to evaluate their association with recurrence at the original surgical site and at new sites. Clinical records and excisional biopsies from 106 equine sarcoids from 64 horses referred to Leahurst Equine Hospital, University of Liverpool, between March 2010 and February 2015 were retrieved. Biopsies were re-evaluated histologically. Clinical data were obtained from hospital records, and owner-reported follow-up data were obtained by telephone questionnaire. Associations between clinical and histopathological features of sarcoids and their recurrence at the surgical site were determined using uni- and multivariable mixed effects logistic regression. Recurrence of sarcoids at the surgical site occurred in 30 horses (46.9%). Sarcoids developed at a distant site in 21 horses (32.8%). In the final mixed effects logistic regression model, only superficial inflammation was associated with reduced odds of recurrence at the surgical site (adjusted odds ratio, 0.32; 95% confidence intervals, 0.10–0.96; P = 0.04). This suggests that the inflammatory process may play a role in protecting horses against the recurrence of sarcoids.

A retrospective study revealed seven cases of coelomic steatitis in adult tentacled snakes (Erpeton tentaculatum), including two males and five females, between May 2014 and August 2020. Common clinical signs included death after unusual floating, generalized weakness, inappetence, reduced body condition, coelomic distension, and reproductive pathology in females. Hematology of one specimen revealed marked monocytosis and lymphocytosis with mild heterophilia (chronic and active inflammation). Gross examination identified variable degrees of intracoelomic fat necrosis in all snakes. Consistent histopathologic features included necrotic adipocytes, lipid saponification, lipofuscin/ceroid deposition, granulomatous inflammation, and multinucleated giant cells (Langhans type). Three females exhibited intralesional yolk fluid associated with periovarian steatitis. Hepatic lipidosis was the second most frequent pathologic finding. Thawed frozen lesser sand eels (Ammodytes tobianus) were fed during this period, stored in vacuum-sealed or opened packets at –18°C (frozen). After the death of the last specimen, vitamin E concentrations and peroxide values of the diet were analyzed. For the sealed and opened frozen batches, respectively, vitamin E concentrations were 0.71 and 0.49 mg/100 g (compared with 4 to 8 mg/100 g in average, fresh, raw mixed eel species samples) and peroxide values were 62.5 and 48.6 meq/kg (exceeding the acceptable peroxide values of 8 meq/kg for fish oils). This case study represents the first report of coelomic steatitis in tentacled snakes of unconfirmed etiology but with a putative association with feeding a long-term frozen-stored sand eel diet containing low vitamin E concentrations and fish oils with high peroxide values at time of analysis.

A 20-year-old British Warmblood gelding was presented for a progressively worsening right forelimb lameness which developed following an intense dressage training session. Initial ultrasound examination revealed a triangular, intrathecal, hypoechoic region within the superficial digital flexor tendon (SDFT) in the proximal, palmar carpal region distal to the accessory carpal bone (ACB), extending 7cm distally into the proximal metacarpal region. No significant improvement in clinical presentation was observed following an eight-week rehabilitation programme. Repeat ultrasound examination revealed an enlarged cross-sectional area of affected tendon. Due to a poor clinical response to conservative treatment, combined with increasingly marked severity of the lameness, the horse was humanely euthanised and the affected SDFT was submitted for macroscopic and histopathological examination at the University of Liverpool. This revealed an approximately 70mm-elongated, focally extensive mass located within the SDFT. On cross-section, the mass was poorly delineated, irregularly triangular, focally haemorrhagic, firm, 15 × 12mm wide and eccentrically placed towards the palmar aspect of the tendon. Histopathological examination identified a moderately to highly cellular, infiltrative, poorly demarcated mesenchymal neoplasm comprised of streams of moderately atypical spindloid cells including bizarre mitoses. Intratendinous fibroma is an uncommonly recorded human neoplasm and this case represents the third reported case of this entity in the horse, the first in an adult horse and the first to be identified in the SDFT.

This case series discusses the clinical presentation, ultrasonographic findings, treatment, and outcome of 5 horses with superficial digital flexor tendon (SDFT) lesions within the carpal canal. The horses’ ages ranged from 11-28 years, and presented with an acute, unilateral forelimb lameness which worsened following proximal limb flexion. The presence of a lesion within the SDFT of the carpal canal was accompanied by a mild swelling of the palmar carpal region in most cases. Diagnostic anesthesia of the ulnar nerve, when performed, abolished the lameness. Ultrasound evaluation revealed an increased cross-sectional area (CSA) of the superficial digital flexor tendon compared to the contralateral, sound limb and a loss of tendon fiber architecture within the palmar aspect of the affected tendon, most readily identifiable upon longitudinal ultrasound images. Three out of the five horses returned to their previous level of performance, and two were euthanized. A back at the knee carpal region conformation was associated with a poorer prognosis in these cases. An intratendinous fibroma was identified on histopathological analysis of one-horse following euthanazia, which has been recorded in a complementary short communication.

An 11 yr old female neutered domestic shorthair presented for an 8 mo history of an asymptomatic abdominal mass. Computed tomography described an irregular, cystic structure closely associated with the duodenum, and focal ultrasonography confirmed the mass shared outer layers with the intestinal wall. Coeliotomy revealed the mass was originating from, and firmly adhered to, the antimesenteric border of the duodenum but was not communicating with the intestinal lumen. En bloc mass resection with omentalization was performed without small intestinal resection. Histopathology confirmed an enteric duplication cyst. The cat made a full recovery and remained asymptomatic postoperatively with no evidence of recurrence. A review of the literature confirms the duodenum to be the most common location of enteric duplication cysts in felines and that subtotal excision is curative in most cases. This differential should be considered in cases of cystic gastrointestinal structures in juvenile and adult felines, with or without associated clinical signs. In cases of luminal involvement or malignant transformation, intestinal resection and anastomosis is more appropriate. This report describes the presentation, investigations, and treatment of an asymptomatic duodenal duplication cyst in an adult feline and summarizes and compares current knowledge of the condition between veterinary and human literature.

A retrospective study revealed ten cases of emphysematous ingluvitis in Loriinae birds from two zoological collections between 2009 and 2020. Common clinical features were sudden death with gas distention of the crop, subcutaneous cervical emphysema and poor body condition, but also included collapse, hypothermia and abandonment. Macroscopic examination revealed moderate crop enlargement, distention and thickening with minimal intraluminal content, and moderate to severe submucosal to transmural gas-filled cysts (emphysema). Histopathology identified widespread transmural multifocal to coalescing empty pseudo-cystic cavities with lytic necrosis, pyo-/granulomatous inflammatory infiltrates, epithelial ulceration, parakeratotic hyperkeratosis, epithelial ballooning degeneration, and occasional intralesional rod-shaped bacteria. The lesion may have impaired the birds' ability to ingest food, resulting in suboptimal body condition. Necrotizing to granulomatous aspiration pneumonia was also a feature in some cases. Anaerobic bacterial culture of four crops identified Clostridium perfringens with associated toxin genes for alpha and occasionally beta2 toxin (cpa and cpb2 genes respectively), by PCR analysis of bacterial isolates cultured from fresh or frozen tissue. C. perfringens was identified as the common etiological agent of emphysematous ingluvitis in crop and/or liver (six out of ten birds), and type A was confirmed in five birds. C. perfringens was not detected in the crop nor liver of two unaffected Loriinae birds. This is the first publication that characterizes nectarivorous bird emphysematous ingluvitis (NBEI), attributes C. perfringens as an etiological agent, and highlights this novel disease as an important cause of death in Loriinae birds, particularly in nestling and fledgling stage of development, but also in older lorikeets and lories.

This study aimed to determine whether a true synovial structure exists over the olecranon tuberosity, which could be attributed to a noninflamed olecranon bursa. Contrast radiography, gross anatomical dissection, and histopathology were used to evaluate the olecranon bursa in horses with no previous elbow pathology. The radiographic study revealed that the contrast was positioned subcutaneously, superficial to the long head of the triceps and its insertion on the olecranon tuberosity and did not extend cranial to the triceps tendon. The contrast region was consistent in shape, size, and location. Gross anatomical dissection of the area revealed a potential bursal space overlying the tendons of the lateral and medial heads of the triceps brachii and the tensor fascia antebrachii in the normal horse. Histopathology confirmed a bursal lining, which was of mesenchymal origin and suggestive of a single-cell membrane, lined by fibroblast-like synoviocytes.

A 9 years and 5 months old, neutered male, Rottweiler was presented for referral at the Small Animal Teaching Hospital, University of Liverpool, for investigations following a fracture of the left femur, which had occurred after minor trauma. Radiographs at the primary veterinary practice revealed a closed, slightly displaced, comminuted, proximal diaphyseal fracture, which had cortical thinning around the fracture site, suggestive of a pathological fracture. Advanced imaging (computed tomography) revealed polyostotic osteolytic lesions which contained contrast enhancing, soft tissue attenuating tissue, associated with cortical destruction throughout the appendicular and axial skeleton. Ultrasound-guided fine needle aspirates of four lesions (right scapular, right femoral, left pelvic and vertebral lesions) were assessed by a boarded clinical pathologist, confirmed diagnosis of a polyostotic osteosarcoma. The patient was euthanased and postmortem examination confirmed the diagnosis.

A neutered female domestic shorthaired cat was presented for a rapidly growing left cervical mass and a 6-month history of primary hyperthyroidism. Cytological examination of the mass was consistent with a sarcoma. Due to poor clinical response the cat was humanely destroyed and a post-mortem examination was performed. This revealed a markedly enlarged, irregularly shaped left thyroid gland with signs of infiltration of the trachea. The contralateral (right) thyroid was also moderately enlarged and irregularly shaped. Histopathological examination of the cervical masses indicated bilateral thyroid carcinosarcomas, evidenced by positive immunohistochemical labelling for vimentin, pan-cytokeratin and thyroid transcription factor-1 of the appropriate cell populations. The cat also had a concurrent pulmonary adenocarcinoma (papillary-lepidic type), unrelated to the thyroid neoplasm. Thyroid carcinosarcoma is an uncommonly recorded canine and human neoplasm and this is the first case of this entity to be reported in a cat.

Although meerkats are commonly kept, neither neoplastic nor non-neoplastic mass lesions are well-described in the scientific literature. Twenty-five histologically diagnosed mass lesions from 21 individuals (10 males, 10 females and one unknown) were extracted/analysed from ante-mortem and post-mortem submissions to IZVG Pathology (2003–2022). Histological diagnoses comprised benign (36%) and malignant (40%) tumours, plus non-neoplastic (NNP) masses (24%). Neoplasms included eight epithelial (lung, liver, gallbladder, uterus, skin), seven mesenchymal (five uterine, two periarticular) and three round cell neoplasms (two intestinal, one hepatic) plus one sex-cord-stromal tumour (testis). All NNP masses were cholesterol granulomas (xanthomas) and found in meninges (n = 4; all male), skin (n = 1, male) or oviduct (n = 1 female). Meningeal xanthomas in males (40%), and uterine neoplasia (four leiomyomas, one leiomyosarcoma and one endometrial adenocarcinoma) in females (42.8%) were the most common lesions. The endometrial adenocarcinoma and two intestinal lymphomas metastasized, mostly to the pancreas [3/3] and the lungs, liver and lymph nodes [each 2/3]. Both non-uterine mesenchymal tumours (sarcomas) were associated with the elbow joint. All lung tumours were benign and epithelial. Three malignant lymphomas were identified, of which two were associated with intestines. The age range and sex ratio for neoplasms were 7 to 16 years (average 9.9 years) and five males to 13 females, and for xanthomas, 3.83 to 9.5 years (average 7.8 years) and five males to one female. Male meerkats appear predisposed to xanthomas (5 males:1 female), particularly meningeal types, whilst neoplastic lesions, particularly of the uterus, predominate in females (92.8%).

Fibrinous polyserositis is commonly associated with various septicaemic bacterial infections, including Escherichia coli in chickens, sucking pigs and other mammals. This presentation has not previously been reported in a rodent. A 5-year-old male red squirrel (Sciurus vulgaris) was submitted from a UK zoological collection for full post-mortem examination after being found dead with no prior clinical signs. The full-body necropsy revealed abundant pale pink, soft and adhesive material associated with the serosal surfaces of various thoracic and abdominal organs (fibrinous pleuritis and peritonitis). Bacterial cultures revealed E. coli (confirmed by MALDI-TOF) as the only common bacterial species in both cavities. Other infectious organisms included Listeria monocytogenes, Proteus spp and Enterococcus spp. Histopathology confirmed severe acute diffuse fibrinous pleuritis, pericarditis and peritonitis, with intravascular gram-negative bacterial emboli (liver, lung, left eye) and concurrent ulcerative enterocolitis with intralesional gram-negative rod-like bacteria. The left eye exhibited severe necrosuppurative retrobulbar cellulitis, resulting in exophthalmos and secondary severe ulcerative keratitis-episcleritis-conjunctivitis and necrosuppurative-haemorrhagic panophthalmitis with intralesional fungal hyphae and coccoid bacteria (most likely either Staphylococcus or Streptococcus spp). The right eye exhibited a cataract, only. There was no evidence of viral inclusion bodies (indicative of, for example, Squirrel adenovirus 1) in any organ. These findings confirm the first report of E. coli-associated fibrinous polyserositis in a red squirrel. The source of the infection could not be confirmed as this was a captive free-living individual; however, such cases may represent potential sources of rodent-borne E. coli infections in zoological collections.

The family Rhinocerotidae includes five near-threatened to critically-endangered species (IUCN Red List). Scientific literature around rhino neoplasia is sporadic and unreviewed. Fifty-nine neoplasms from 49 rhinos were reviewed from IZVG Pathology (n = 7 individuals) and current scientific literature (18 peer-reviewed publications, using Google Scholar/PubMed keywords “rhinoceros”, “tumor”, and “neoplasia”). Species included greater one-horned (n = 27), southern white (n = 15), southern black (n = 4), Sumatran rhinoceros (n = 2) and non-specified (n = 1). In 20.3% of individuals, neoplasia led to death or was life-threatening without treatment. 6.8% of all tumours metastasized (no organ predisposition). Benign/malignant tumours comprised 55.9/42.4% respectively. Primary female non-ovarian reproductive tract (NORT) tumours were most frequent (57.6%; 12.1% malignant) followed by cutaneous squamous cell carcinomas (SCCs) (13.6%). Of nine SCCs, eight affected southern white rhinos. By species the commonest tumours were: greater one-horned - NORT leiomyoma (79.3%); southern white - SCC (35%); southern black - melanocytic tumours (2/4); and Sumatran - NORT leiomyoma (2/3). Southern black rhinos were younger (average 8.4 years) and mostly male with malignant tumours (acute lymphoblastic leukaemia, cutaneous malignant melanoma, malignant seminoma). Greater one-horned (average 22.9 years) and Sumatran rhinos were mostly females with NORT leiomyomas (87% and 2/3 tumours, respectively). White rhinos (average 39 years) exhibited a 50:50 sex ratio and 70% malignant tumours (eight SCCs, two malignant seminomas and single cases of ovarian adenocarcinoma, prostatic carcinosarcoma, adrenocortical carcinoma and cutaneous soft tissue sarcoma) and a 10% metastatic rate. NORT leiomyomas and SCCs are most common in greater one-horned and southern white rhinos, respectively. Metastatic neoplasia appears rare.

Lions (Panthera leo) are a key charismatic zoo species, but the scientific literature concerning neoplastic disease is scattered with limited reviews. One-hundred-and-forty neoplasms from 133 lions (0.5 to 26 years old) were reviewed from IZVG Pathology, Easter Bush Pathology and current scientific literature (31 peer-reviewed publications, using Google Scholar/Pubmed keywords: “Panthera leo”, “tumor”, and “neoplasia”). In 61.7% of individuals, neoplasia led to death or was life-threatening without treatment. 39.8% of all tumours metastasized. Primary neoplasms most frequently arose from mammary glands (17.1%), skin (15.7%) and lymph nodes or spleen (13.6%). Metastasized organs included liver (24.3%), lymph nodes (20.0%), spleen (15.0%), and lung (14.3%). Malignant/benign tumours comprised 76.4%/23.6%, respectively. Mammary gland adenocarcinoma [MGA] (15.7%) and lymphoma (15.0%) were most common. Skin (29% fibrosarcoma, 29% epithelial, 20% melanocytic, 10% piloleiomyosarcoma), parathyroid gland (adenoma), gallbladder (adenocarcinoma/adenoma: 60%/40%), intestines (adenocarcinoma), mammary gland (all malignant epithelial), testes (germ cell/stroma) and bone (osteosarcoma/myeloma) exhibited only primary tumours. Mean ages of specified African (n = 50), white African (n = 6) and Asian lions (n = 19) were 16, 12 and 12.6 years, respectively. Barbary lions (n = 3) were all >16 years old. Females dominated sex ratios in African (62%), and white African populations (100%). By subspecies the commonest tumours were: African: MGA (27.3%); white African: cutaneous mesenchymal tumours (57.1%); and Asians: haemangiosarcoma (42.1%). Three Barbary lions exhibited respectively MGA (pulmonary/hepatic/splenic/renal metastasis), uterine adenocarcinoma (pulmonary metastasis) and splenic erythrophagocytic T-cell lymphoma (nodal metastasis). Metastasizng malignant neoplasms of mammary gland and lymphoid origin are dominant in lions (>12 years).

Equine gastric ulcer syndrome (EGUS) describes the general erosion and inflammation of the horse’s distal oesophageal, gastric or proximal duodenal epithelium due to prolonged exposure to acidic gastric fluid. Lesions may be divided into equine squamous gastric ulcer syndrome (ESGUS) and equine glandular gastric ulcer syndrome (EGGUS). A scoring system adapted from Andrews et al. (1999) interpreted severity and lesion number to determine the extent of EGUS. The aim of this project was to describe and grade the histological findings of series of glandular lesions and relate endoscopic and histological findings. This study included 106 horses with a presumptive clinical diagnosis of gastritis. Endoscopic examination allowed for the visualization of the glandular mucosa and identification and grading of mucosal lesions (0–4). Endoscopic pinch biopsies were taken and processed routinely. A novel histological grading scheme (0–3) was applied to each case. Endoscopic findings revealed a large majority of the lesions were of intermediate severity (grades 2 and 3) with fewer mild (1) and severe (4) lesions. The histopathological finding was of an exudative, fibrinosuppurative gastritis, with varying degrees of ulceration and architectural alteration of the mucosa. The severity of the histological change correlated closely with the endoscopic findings. This work has characterized equine glandular gastritis lesions as being of a range of severities by endoscopic examination. The histological lesion is of an ulcerative and exudative fibrinosuppurative gastritis and that the severity of gross and histological lesions correlate closely.

A neutered female domestic shorthaired cat was presented for a rapidly growing left cervical mass and a 6 month history of primary hyperthyroidism. Cytological examination of the mass was consistent with a sarcoma. Due to poor clinical response the cat was humanely destroyed. The cat was submitted for post-mortem examination. The cat underwent a standard full post-mortem examination. Sections of relevant tissues were processed for histological examination. Sections of the significant lesions were immunolabelled for vimentin, cytokeratin and thyroid transcription factor-1 (TTF-1). Examination of the neck confirmed a large mass (30 mm maximum diameter) arising from the cranial pole of the left thyroid gland. On histopathological examination, both thyroid glands exhibited the same features. Markedly expanding the thyroid gland, with peripheralization and compression of normal thyroid tissue, there was a large, infiltrative, poorly demarcated, non-encapsulated multinodular neoplasm composed of two main cell populations, which were largely distinct from each other, but with some intermingling. The predominant population consisted of short streams and bundles of highly pleomorphic spindle-shaped to oval cells; the other cell population consisted of dense arrangements of small, often irregular follicular structures, lined by a relatively monomorphic population of polygonal cells. The spindle cells were diffusely vimentin positive; the follicular cells were cytokeratin and TTF-1 positive. This is a case of thyroid carcinosarcoma, a highly unusual neoplasm in which a malignant neoplastic process consists of both epithelial and mesenchymal elements. This is the first report of this entity in the cat.

Although the equine sarcoid is the most common skin neoplasm in domesticated horses, histopathological characteristics have not previously been evaluated for association with recurrence. The aim of this retrospective cohort study was to investigate clinical and histopathological features of excised equine sarcoids and to evaluate their association with recurrence at the original surgical site and at new sites. Clinical records and excisional biopsies from 106 equine sarcoids from 64 horses referred to Leahurst Equine Hospital, University of Liverpool, between March 2010 and February 2015 were retrieved. Biopsies were re-evaluated histologically. Clinical data were obtained from hospital records, and owner-reported follow-up data were obtained by telephone ques tionnaire. Associations between clinical and histopathological features of sarcoids and their recurrence at the surgical site were determined using uni- and multivariable mixed effects logistic regression. Recurrence of sar coids at the surgical site occurred in 30 horses (46.9%). Sarcoids developed at a distant site in 21 horses (32.8%). In the final mixed effects logistic regression model, only superficial inflammation was associated with reduced odds of recurrence at the surgical site (adjusted odds ratio, 0.32; 95% confidence intervals, 0.10–0.96; P = 0.04). This suggests that the inflammatory process may play a role in protecting horses against the recurrence of sarcoids.

Entamoeba invadens is an amoeboid protozoan known to be highly pathogenic in lizards and snakes. A single PCR-confirmed case is documented in a river turtle but reports of presumptive cases affecting terrestrial chelonians lack molecular confirmation by PCR testing. This presentation documents a rare outbreak of PCR-confirmed E. invadens infection in three co-housed terrestrial chelonians. Three deceased Home’s hingeback tortoises (Kinixys homeana) were submitted by a zoological collection over a 2-month period for full post-mortem examination. Primary gross lesions included: 1) hepatomegaly with multifocal, 2–5 mm diameter, pale-cream/tan, irregularly circular depressions rimmed by melanin pigment over the capsular surface and cut surfaces; and 2) catarrhal colitis with diffuse submucosal oedematous thickening, reddened mucosa and moderate amounts of intraluminal mucoid fluid. Direct microscopy of colonic content revealed moderate numbers of large ciliate protozoa (consistent with Balantidium coli) and low numbers of smaller non-ciliate amoeba-like protozoa. Main histological lesions included: 1) marked, multifocal to coalescing random acute hepatic necrosis with intralesional protozoa (consistent with Entamoeba spp) and occasional multifocal bacillary bacterial colonies; and 2) marked subacute diffuse erosive and heterophilic colitis with submucosa oedema and intralesional (Entamoeba-like) protozoa and mixed colonizing bacteria. Pooled liver samples were positive on PCR analysis for Entamoeba spp and E. invadens. This PCR-confirmed outbreak of E. invadens infection substantiates past suspicions that this Entamoeba species can induce clinical disease in terrestrial chelonians and may be transmissible. Whilst the source of infection was unknown, co-housed reptiles or faecal contamination cannot be excluded.

Common octopus are frequently kept in aquaria and identifying anatomy can be challenging. Whole octopus are not regularly submitted for full diagnostic post-mortems examinations (PME) rather biopsied samples for histopathological assessment are more common, usually from an unknown organ. This poster aims to be a visual aid for PME performed by clinicians or aquarists and provides normal histology for reference. A 2.8 kg adult female octopus was submitted for PME at the International Zoo Veterinary Group (IZVG) from a European aquarium in February 2022, after being found dead in its enclosure after a short period of inappetence. On PME, organs were photographed and documented, for future reference, to aid in identifying organs from this species. The PME of this specimen identified early cortical bilateral cataracts and an empty gastrointestinal system, following clinical signs of anorexia. No other gross pathological lesions were identified. Histopathology revealed ulcerative bacterial stomatitis and oesophageal coccidiosis, which impaired the individual's ability to feed. Additionally, this female exhibited reproductive senescence, which is a common lesion found in geriatric octopuses. Normal organ histologic photomicrographs, from previous cases within the IZVG database, have been included for completeness. Octopus anatomy can be daunting and confusing. This visual aid poster should be used to guide future PME and help increase knowledge of normal anatomy in this alien species. (cabidigitallibrary.org/doi/full/10.5555/20240380479).

A 10-year-10-month-old, intact female Asian Small-Clawed Otter (Aonyx cinerea) with chronic bilateral renal calculi presented with lethargy and inappetence - which worsened over 3 days. Clinical examination under anaesthesia was performed following clinical signs of stranguria. Diagnostic imaging revealed no changes in renal calculi distribution, and blood analysis was also performed. Ultrasonographic evaluation showed severe wall thickening of both uterine horns and a mild amount of intrauterine fluid accumulation. The bladder was small and no uroliths were identified. Mild purulent discharge from the vulva was detected. Symptomatic treatment with amoxicillin-clavulanic acid (Synulox® 50 mg tablets), meloxicam (Loxicom® 1.5 mg/ml) and subcutaneous fluid therapy was initiated. Due to anorexia (>24 hrs), the decision was made to perform an ovariohysterectomy within 24 hrs, under general anaesthesia. Histopathology confirmed the diagnosis of pyometra, with concurrent marked, chronic, diffuse cystic endometrial hyperplasia, plus multifocal areas of cellular dysplasia and increased mitotic activity. Bacterial cultures identified Coagulase-negative Staphylococcus spp. sensitive to Amoxicillin. The otter was postoperatively isolated from its group in a 4x4 sqm indoor enclosure without access to a pond. Consistent oral medication was achieved. The surgical wound healed well, and the animal was uneventfully reintroduced to its two partner animals 10 days later. This case shows successful surgical and postoperative management of pyometra in an Asian Small-Clawed Otter and first documentation of Coagulase-negative Staphylococcus spp. associated with pyometra in this species.

A well-established group of thirteen Humboldt penguins (Spheniscus humboldti) of mixed age and sex were moved to an adjacent enclosure to facilitate pool renovation. An unremarkable return move was carried out twenty-three days later. The first of eight deaths occurred ten days later with the remaining over a period of four weeks. Initial non-specific presenting signs included weakness, lethargy and inappetence. Some individuals displayed neurological signs (torticollis and ataxia) and respiratory signs (increased effort and depth). Following the death of the third penguin, APHA were notified regarding Avian Influenza suspicions and restrictions were implemented whilst awaiting results (negative). Post-mortem examinations including histopathology alongside culture and sensitivity were used to determine cause of deaths. Bilateral vacuolar leukoencephalopathy with features reminiscent of "Wernicke-like encephalopathy" was found consistently on histopathology (suggestive of Thiamine (Vitamin B1) deficiency) with some birds also suffering from a variety of secondary conditions such as aspergillosis, chronic diffuse lymphoplasmacytic enterocolitis, cholangiohepatitis or chronic air sacculitis. Response to sole treatment with parenteral Vitamin B1 was rapid in one penguin showing acute onset neurological signs: with complete resolution within forty-eight hours. Extended storage length of frozen fish for feeding and inadequate vitamin supplementation along with the additional stress of moving enclosures was thought to have contributed to the deaths. Thawed frozen fish has been shown to contain inadequate levels of vitamin B1 when compared to Association of Zoos and Aquariums dietary recommendations for Humboldt penguins (Bos et al., 2018). These contributing husbandry factors have now been addressed, and no further clinical signs or deaths have been reported in the last seven months.

In the reptilian veterinary literature, snakes (suborder Serpentes) are over-represented for neoplastic disease, although estimated prevalence varies (Page-Karjian et al., 2017; Duke et al., 2022). As improved husbandry increases captive lifespans and diagnostic capabilities advance (Christman et al., 2017), concerns surrounding neoplasia escalate. This retrospective study assessed the prevalence of neoplasia in routine snake submissions to IZVG pathology (2003-2023). 1146 histology and cytology samples (comprising 894 individual snakes, 87 species, and 11 families) were examined by specialist veterinary pathologists, revealing 148 neoplasms which were subsequently assessed for associations between species, age, sex, primary organ, histogenesis, and malignancy. Overall neoplastic prevalence was 16.6% (n=148). Colubridae were over-represented (n=103, 69.6% of neoplasms; 30.8% of Colubridae submissions), with a significantly higher prevalence than the study population (p< 0.005). Of colubrids, the two primary genera were Pantherophis (corn snakes/rat snakes; n=60/103, 40.5%) and Lampropeltis (king snakes/milk snakes; n=24/103, 16.2%). Mean age at diagnosis was 9 years (range: 2 to 21 years) with no age trends or sex predisposition identified. Overall, organ system prevalences were: 29.1% (n=43/148) integumentary; 18.9% (n=28/148) digestive (alimentary tract/liver/gallbladder); 9.5% (n=14/148) urinary; 6.8% (n=10/148) multicentric neoplasms of unknown origin; 5.4% (n=8/148) musculoskeletal; 3.4% (n=5/148) reproductive; 3.4% (n=3/148) coelom; 1.4% (n=2/148) body wall; 0.7% (n=1/148) optical; and 0.7% (n=1/148) endocrine. Location was unspecified for 21% (n=31/148) neoplasms. Malignant neoplasia predominated (n=123/148, 83.1%), including 58.5% (n=72/123) mesenchymal, 34.1% (n=42/123) epithelial, and 7.3% (n=9/123) round-cell lineages. Only 12.8% (n=19/148) neoplasms were benign. Spindle cell sarcomas were dominant (n=45/148, 30.4%) followed by adenocarcinomas and carcinomas (n=21/148, 14.2% each). Lymphoid/haematopoietic neoplasms were less prevalent (n=8/148, 5.4%). 13 lipomas (8.8%) were detected, with corn snakes (P. guttatus) predisposed. Chromatophoromas were rare (n=5/148, 3.4%), including 4 melanophoromas and 1 iridophoroma. Continued surveillance with further clinical and histological investigations are required to establish risk factors and aetiologies for ophidian neoplasia.

Macropodidae (e.g., kangaroos, wallabies etc.) are increasingly common in UK zoos; however, scientific literature describing cardiomyopathies in this family is scarce. Reported conditions include: (1) Toxoplasmosis in red kangaroos and Bennett's wallabies, (2) Takotsubo-like cardiomyopathy in a Bennett's wallaby, and (3) primary hypertrophic cardiomyopathy (HCM) in a Rock kangaroo, a Matschie's tree kangaroo, and two Bennett's wallabies. Specific aetiologies for primary HCM in these species are unknown; but genetic factors likely influence the condition (e.g., like MYBPC3 genetic mutations in Ragdoll and Maine Coon cats). Parma wallabies are a near-threatened species, and research into their predisposed conditions is vital to their conservation. To date, HCM in Parma wallabies has not been described. Two adult male Parma wallabies from two separate herds were submitted to IZVG pathology for full post-mortem examination between 2020 and 2023. Both died spontaneously without detectable clinical signs of heart failure. Gross examination revealed globoid hearts, with marked concentric left ventricular hypertrophy and marked diffuse pulmonary congestion with oedema in both wallabies. The second specimen also exhibited agonal aspiration of gastric content and multifocal, small (1-3 mm) diameter circular areas of LV myocardial pallor. Heart wall measurements were LV-12 mm, IVS-11 mm and RV-2 mm, with an LV-to-RV ratio of 6:1 (>3.5, indicating left ventricular hypertrophy). Luminal diameters were LV-11 mm and RV-8 mm. Cardiac lesions were histologically limited to mild cardiac myofibre disarray and moderate myofibre hypertrophy (anisokaryosis/anisocytosis). Pulmonary lesions included bronchioloalveolar oedema with minimal to mild accumulations of haemosiderin-laden macrophages ("heart-failure cells"). A specific aetiology for HCM was not determined in either animal, however concurrent diseases (e.g., bilateral thyroid hyperplasia, or aortic atherosclerosis) were absent. The gross and histology changes in both specimens are consistent with primary (idiopathic) HCM, as previously described in other macropods.

As one of the more charismatic zoo families, penguins (Spheniscidae) are frequently popular zoo exhibits which generate much public attention and support. Only nine of the eighteen penguin species recorded by the IUCN are kept in UK zoos, the most common being Humboldt's, Gentoo, African, and Rockhopper penguins. Every so often, however, outbreaks of sudden death occur in captive collections which, if severe losses occur, can result in the complete collapse of the colony's social infrastructure. These mortality events can be clinically frustrating to manage and resolve, and rely on effective collaborations between the clinicians, pathologists, ancillary diagnostic labs, and zoo husbandry staff. Such cases can be similarly challenging for diagnosticians if the approaches to history taking, necropsies and sample-taking are inconsistent and/or incomplete across all cases, which relies on all those involved being kept informed on recent developments in newly described and re-evaluated diseases in penguins. Classic sudden death scenarios include aspergillosis in colder months and avian malaria in warmer months; however, other infectious diseases and diseases associated with recent stressors (e.g., transport), enclosure design, and diet are either poorly described or absent in the current literature, despite popular textbooks being available for reference. Until this information is more readily available, it is vital that the experience of those who regularly work with penguins share such knowledge until further studies are performed. This masterclass aims to equip clinicians with up-to-date knowledge of penguin diseases and a practical approach to effectively investigating mortality events in captive penguins, in collaboration with experienced pathologists.

Are you ready to face the zoo quiz challenge yet again? Following the first IZVG Pathology Photoquizoo in 2019, and in the footsteps of Vic Simpson, we present a second instalment of our illustrated pathology quiz. You will be presented with a series of PowerPoint slides (e.g. see Figure 1) demonstrating pathology entities and diseases from our archive, each accompanied by 1 or more corresponding questions. Basic information on the case (for example affected species) will be provided. Questions can range from "Morphological diagnosis" / "Name the parasite" / "Aetiology" / "Life-cycle" to "Name the disease" and more. Each slide will be presented at an automated time interval during which you can record your answer/s on your quiz sheet (this will be provided separately). Upon completion of the quiz your answers will be marked by another member of the audience - use an anonymous identity on your quiz sheet - whilst we discuss the answers in the second part of the session. Participants will receive a handicap based on professional experience, and the highest score will receive a prize.