Cutaneous melanoma in a red-footed tortoise (Chelonoidis carbonaria)

There are few clinical reports of melanomas in reptiles. A 10-year-old male red-footed tortoise (Chelonoidis carbonaria) was referred to the Veterinary Hospital presenting with an ulcerated mass in the lateral aspect of the left pelvic limb. Radiographs demonstrated swelling and increased soft tissue density overlying the femur, tibia, and fibula, without bone involvement. Fine-needle aspiration cytology revealed innumerable round cells, with a defined cytoplasm filled with fine brown-black granules (melanin), which were considered well-differentiated melanocytes, suggesting a case of cutaneous melanoma. The mass was surgically removed. It was encapsulated and had an abundant blood supply. Histopathological examination revealed a well demarcated and encapsulated neoplastic proliferation of mesenchymal cells, with high cellularity and moderate fibrous stroma. Lymphangiectasia in the dermis adjacent to the tumor was also observed. Immunohistochemistry confirmed the diagnosis, with cells staining positive for Melan-A antibody being observed in neoplastic proliferation, adjacent dermis, inside lymphatic vessels, and invading the delimiting tumor's capsule. There was no evidence of local or systemic recurrence of the neoplasm over 500 days after removal. Chelonians can be affected by cutaneous melanomas. Surgical removal in this case was curative.     

Cutaneous melanoma in a ferret (Mustela putorius furo)

A 4-year-old spayed female ferret (Mustela putorius furo) was clinically evaluated for a slightly raised subcutaneous mass in the dorsal lumbar area. The mass was surgically excised and submitted for histopathologic evaluation. Histologically, the mass was composed of closely packeted large, atypical, polygonal to spindle-shaped cells arranged in sheets and short bundles. A few cells contained variable amounts of granular, brown to black intracytoplasmic pigment. Warthin-Starry and Fontana-Masson silver stains demonstrated variable numbers of fine black intracytoplasmic granules in most cells. The atypical cells stained positively for vimentin and S100 protein and negatively for cytokeratin and Melan A. Ultrastructurally, the neoplastic cells contained intracytoplasmic melanosomes in different stages of development. Compound melanosomes were not identified. To our knowledge, this report documents the first case of a spontaneous cutaneous melanoma in the ferret.     

Haemangiopericytoma in a calf

After castration, a Japanese Black male calf developed subcutaneous tumours near the scrotum. They were surgically excised, and no recurrence was detected two years after surgery. The tumours were characterised by neoplastic cells concentrically arranged around blood vessels of various sizes. The neoplastic cells contained many cytofilaments, and the majority of the cells expressed smooth muscle actin, but focal densities were not found. On the basis of the immunohistochemical and ultrastructural features. the tumours were considered to be of pericyte origin.     

Lactation in a calf

Extract

An Ayrshire heifer calf, 10 days old, which had been lactating from the day of birth.     

Mesothelioma in a calf

A 5-month-old Holstein heifer was hospitalized because of progressive abdominal distention and decreased growth rate. It had continued to eat and was alert until 5 days before hospitalization. High BUN and serum aspartate transaminase values, hypoproteinemia, and a stress leukogram were ascertained from clinicopathologic evaluation. Oral electrolyte therapy was begun, but the calf died. Necropsy revealed multiple nodules (0.5 to 6 cm diameter) attached to the peritoneum, throughout the abdominal cavity. The histopathologic diagnosis was mesothelioma.     

Melanosis maculosa in a calf

This work describes findings in a fattened calf, which were seen in a routine slaughter. The most important findings by the meat inspector were diffuse, black spots between 2 and 70 mm in diameter. This hyperpigmentation was observed on the entire carcass as well as on the outside and inside of all internal organs. Removal of the spinal cord produced black colored liquor. Subsequent microbiological examination of the meat resulted in sterile findings. The muscle pH was 5.8. On histological examination many macrophages containing melanin were found in the lung and liver. Based on these findings the diagnosis of Melanosis maculosa was made.