MAST CELL TUMORS IN CHEETAH (ACINONYX JUBATUS): A CASE SERIES.

Mast cell tumors in nondomestic felids are rarely reported and their biological characteristics are not well described. A retrospective review of the pathology records of 52 zoo-housed cheetahs (Acinonyx jubatus) identified five cases of mast cell tumor, involving four closely related individuals. The age at initial presentation varied from 14 mo to 6 yr. Four cases presented as solitary or multiple cutaneous masses that were mostly slow growing, up to 20 mm diameter, and predominantly nonulcerated. The diagnosis was made by fine needle aspiration cytology of a lesion in one case and by excisional biopsy in the others. Histopathologically, the lesions resembled low- to intermediate-grade canine mast cell tumors, with variations in the degree of anisocytosis and anisokaryosis. Surgical excision was incomplete for 80% of the cutaneous lesions, but local recurrence was not observed in any case. One animal with cutaneous lesions subsequently developed fatal visceral mastocytosis involving the spleen, liver, and adrenal gland. There was no evidence of lymph node invasion or paraneoplastic gastrointestinal signs in any of the cases.

Nutritional status and functional digestive histology of the carnivorous Tasmanian devil (Sarcophilus harrisii).

Tasmanian devils (Sarcophilus harrisii) are the largest carnivorous marsupial in Australia. Currently many animals are being held in captivity as a management procedure to combat Devil Facial Tumor Disease. Only one published study thus far has investigated nutrition in Tasmanian devils, determining their maintenance energy requirements and digestibility on a rodent diet. More information is needed on Tasmanian devil nutritional and gastrointestinal function to aid in their management. Our study aimed to investigate the current nutritional status of Tasmanian devils in a captive population and functional morphology and histology of their gastrointestinal tract. Animals were maintained on a diet of kangaroo, rabbit, quail and chicken wings and digestibility of these items by the devils was high (>85% for dry matter, protein and lipid). Kangaroo and rabbit were high protein diet items while the quail and chicken wings provided high lipid to the diet, and carbohydrates were minimal (≤3% energy). Maintenance energy requirements were determined to be 620kJkg-0.75d-1 with no significant difference between males and females. Opportunistic samples for gastrointestinal morphology were obtained from captive specimens. Tasmanian devils have a simple digestive tract similar to other dasyurid species. Both the morphology and histology of the gastrointestinal tract show specialization for a high protein carnivorous diet.

Hepatic fibrosarcoma incarcerated in a peritoneopericardial diaphragmatic hernia in a cat.

CASE SUMMARY: A 14-year-old, female neutered domestic shorthair presented for dyspnoea. Thoracic ultrasonography and radiography showed that a heterogeneous mass was present within the pericardial sac, and the mass continued caudally with the mesenteric fat. On CT, the outline of the diaphragm was not continuous and there was an obvious defect with diaphragmatic thickening present at the mid-level of the liver. A pleural effusion and a small-volume pericardial effusion were also present. A ventral midline coeliotomy and median sternotomy revealed a 5 × 6 × 7 cm firm, irregular, tan-coloured soft tissue mass within the pericardial sac attached to both the diaphragmatic defect and liver. The mass was carefully dissected away from the heart and the diaphragmatic defect was repaired with primary closure. Postoperatively, the cat had a persistent pneumothorax that required continuous pleural suction for 41 h. The cat died 44 h postoperatively. Histopathology and immunohistochemistry confirmed the mass to be a hepatic fibrosarcoma incarcerated in a peritoneopericardial diaphragmatic hernia (PPDH). RELEVANCE AND NOVEL INFORMATION: This is the first reported case of metaplastic transformation of liver into a sarcoma in a cat with PPDH. In addition, hepatic fibrosarcoma is a rarely reported location for fibrosarcoma in this species.

Nasofacial infection in a cat due to a novel bacterium in Neisseriaceae.

CASE SUMMARY: A 2-year-old female spayed domestic shorthair cat was presented for a progressive subcutaneous nasofacial swelling. Histology of biopsy tissue revealed pyogranulomatous inflammation and large numbers of gram-negative capsulated bacterial coccobacilli within macrophages. The isolate was fastidious and grew after 6 days under microaerophilic conditions in a candle jar. The molecular identity of the isolate, from comparative sequence analysis of the 16s rRNA gene, is an as yet to be classified bacterial species within a novel genus of Neisseria. Infection resolved after 7 months of antimicrobial therapy with doxycycline and trimethoprim sulfamethoxazole. There has been no further recurrence of clinical signs in a 3 year follow-up period. RELEVANCE AND NOVEL INFORMATION: Cats are susceptible to nasofacial infections as a result of traumatic inoculation of environmental bacteria, fungi and protozoa. We report a novel pathogen in the Neisseriaceae family, identified by 16 sRNA comparative sequence analysis, as a cause of nasofacial infection in a cat, and its subsequent successful treatment with combination antimicrobial therapy.

Papillomavirus-associated multicentric squamous cell carcinoma in situ in a cat: an unusually extensive and progressive case with subsequent metastasis.

BACKGROUND: Multicentric squamous cell carcinoma in situ (MSCCIS) is an uncommon cutaneous disease of middle-aged to older cats, with some cases being linked to papillomavirus infection. The disease course is usually benign. Initial eruption of multifocal, pigmented, hyperkeratotic plaques is typical, with gradual progression to thickly crusted ulcerative lesions. ANIMAL: A 5-year-old male neutered Devon rex cat in apparent good health was initially presented with a 16 month history of over 40 nonpruritic dorsally distributed hyperpigmented patches. Lesions progressed gradually over 2 years to larger, more pigmented, crusted plaques and ulcerated nodules. At 7 years of age the cat developed neurological signs and systemic illness and was euthanized. METHODS AND RESULTS: Initial skin histopathology revealed discrete regions of epidermal and follicular epithelial hyperplasia, with moderate numbers of apoptotic keratinocytes, and mild focal epithelial dysplasia. A diagnosis of erythema multiforme was considered; feline herpesvirus-1 immunohistochemistry was negative. Repeat histopathology 22 months after initial presentation confirmed MSCCIS with foci of invasive squamous cell carcinoma (SCC). Postmortem examination 1 month later revealed SCC within the thoracic wall, lungs and vessels of the thoracic spinal cord and heart base, presumed to be metastases from skin lesions. Fluorescent in situ hybridization of initial and later histopathology samples was positive for Felis domesticus papillomavirus type 2. Immunoreactivity of p16 was prominent within early and late cutaneous lesions and internal SCCs. CONCLUSIONS: This case represents an unusual presentation of papillomavirus-associated MSCCIS with extensive lesions, atypical initial histopathology and progression to SCC with distant metastases.