Suspected pseudohypoparathyroidism in a domestic ferret

A 1.5-year-old ferret examined because of seizures was found to have low serum calcium, high serum phosphorus, and extremely high serum parathyroid hormone concentrations. Common causes of these abnormalities, including nutritional secondary hyperparathyroidism, chronic renal secondary hyperparathyroidism, tumor lysis syndrome, and hypomagnesemia, were ruled out, and a tentative diagnosis of pseudohypoparathyroidism was made. Pseudohypoparathyroidism is a hereditary condition in people that, to our knowledge, has not been identified in ferrets previously and is caused by a lack of response to high serum parathyroid hormone concentrations, rather than a deficiency of this hormone. The ferret improved after treatment with dihydrotachysterol (a vitamin D analog) and calcium carbonate. It was still doing well after 3.5 years of continued treatment.     

Eosinophilic gastroenteritis in a domestic ferret

Eosinophilic gastroenteritis without peripheral eosinophilia was diagnosed histologically in a 5-year-old neutered male ferret showing acute signs of projectile vomiting, dark mucoid diarrhea, and chronic weight loss for 2 mo. The ferret was clinically normal after 4 days of treatment with parenteral fluids, antibiotics, and corticosteroids.     

Lipid-rich carcinoma of the mammary gland in a cat

A 1.5-year-old female, intact, clinically healthy cat presented for a subcutaneous mass of the ventral abdomen. Surgical excision and microscopic examination of the mass were performed. Histologically, this was a discrete, unencapsulated, multilobular, expansile mass, which compressed the surrounding normal mammary tissue. Lobules were composed of tubuloacinar structures formed by atypical round to polygonal cells, which contained foamy to microvacuolated cytoplasm and variably sized, intracytoplasmic, distinct vacuoles causing nuclear peripheralization. Neoplastic cells demonstrated intense and diffuse immunoreactivity for cytokeratin and lacked immunoreactivity for vimentin. The vacuolar contents stained positively with Oil RedO and negatively with periodic acid-Schiff and Alcian blue stains. Histomorphologic, histochemical, and immunohistochemial analysis support a diagnosis of lipid-rich mammary carcinoma. This is the first report of a cat with a lipid-rich variant of mammary carcinoma.     

Zygomatic salivary gland mucocele in a ferret

A zygomatic salivary gland mucocele was diagnosed in a 1-year-old female domestic ferret with exophthalmos. A T-shaped incision from near the lateral canthus to the base of the ear and continuing ventrally to the level of the commissure of the mouth was made to expose the mucocele. Surgical removal was complicated by the large open orbit of the ferret, adjacent cellulitis, extension ventromedial to the globe, and difficulty in identifying important motor nerves. Vision was maintained, but slight postoperative enophthalmos and mild upper eyelid paresis developed.     

Invasive ductal carcinoma of the mammary gland in a mare

A 21-year-old thoroughbred mare had a 35 x 14 x 10 cm mass involving the mammary gland. Metastases were found in the kidneys, lungs, skeletal muscles, and regional lymph nodes. Histopathologic examination of the tumor revealed a ductal solid carcinoma with extensive intraductal and intralobular involvement and focal infiltration of the adjacent stroma. The intralobular neoplasms were divided into irregularly shaped islands and sheets of polygonal and spindle-shaped epithelial cells by thick or thin fibrous connective tissue bundles. The neoplastic cells had a small or moderate amount of cytoplasm that stained faintly with eosin and round or oval hyperchromatic nuclei. Immunohistochemically, the neoplastic cells were strongly positive for Lu-5, weakly positive for AE1/AE3, vimentin, and glial fibrillary acidic protein, and negative for cytokeratin 8, cytokeratin 14, alpha-smooth muscle actin, calponin, and S100. The neoplasm was diagnosed as an invasive ductal carcinoma of the mammary gland with multiple metastases.     

Myofasciitis in the domestic ferret

Since late 2003, an inflammatory disease of muscle and fascia has been diagnosed in several ferrets at Northwest ZooPath, and this report describes the condition in 17 ferrets. It is a disease of young ferrets, characterized by rapid onset of clinical signs, high fever, neutrophilic leukocytosis, treatment failure, and death (or euthanasia). Gross lesions include atrophy of skeletal muscle; red and white mottling and dilatation of the esophagus; and splenomegaly. Histologically, moderate to severe suppurative to pyogranulomatous inflammation is in the skeletal muscle and the fascia at multiple sites, including esophagus, heart, limbs, body wall, head, and lumbar regions. Myeloid hyperplasia of spleen and/or bone marrow also is a prominent feature. Ultrastructural lesions include mitochondrial swelling, intracellular edema, disruption of myofibrils and Z bands. Bacterial and viral cultures, electron microscopy, immunohistochemistry, and polymerase chain reaction were negative for a variety of infectious agents. The clinical presentation and distribution of lesions suggests that polymyositis in domestic ferrets is likely a distinct entity. The etiopathogenesis if this condition is not known.     

Cytochrome b5 expression in gonadectomy-induced adrenocortical neoplasms of the domestic ferret (Mustela putorius furo)

Whereas the adrenal glands of healthy ferrets produce only limited amounts of androgenic steroids, adrenocortical neoplasms that arise in neutered ferrets typically secrete androgens or their derivative, estrogen. The 17,20-lyase activity of cytochrome P450 17alpha-hydroxylase/17,20-lyase (P450c17) must increase to permit androgen biosynthesis in neoplastic adrenal tissue. We screened ferret adrenocortical tumor specimens for expression of cytochrome b(5) (cyt b(5)), an allosteric regulator that selectively enhances the 17,20-lyase activity of P450c17. Cyt b(5) immunoreactivity was evident in 24 of 25 (96%) adrenocortical adenomas/carcinomas from ferrets with signs of ectopic sex steroid production. Normal adrenocortical cells lacked cyt b(5), which may account for the low production of adrenal androgens in healthy ferrets. Other markers characteristic of gonadal somatic cells, such as luteinizing hormone receptor, aromatase, and GATA4, were coexpressed with cyt b(5) in some of the tumors. We concluded that cyt b(5) is upregulated during gonadectomy-induced adrenocortical neoplasia and is a marker of androgen synthetic potential in these tumors.     

Secretory carcinoma of the canine mammary gland

Secretory carcinoma is an uncommon variant of breast cancer, characterized by the presence of intracellular and extracellular eosinophilic secretion. Here, we report the cytologic, histologic, and immunohistochemical findings of a secretory carcinoma diagnosed in the left inguinal mammary gland of a 3-year-old female German Shepherd Dog. The fine-needle aspiration cytology showed numerous large branching sheets of neoplastic cells and isolated cells with cytoplasmic vacuoles. Histologically, the tumor was composed of cells with clear cytoplasm and prominent vacuoles that pushed the nuclei to the periphery, resembling signet ring cells. These cells were arranged in solid or tubular structures with lumenal spaces filled with eosinophilic secretion. Immunohistochemical reactions to cytokeratin (CAM 5.2) and alpha-lactalbumin were strongly positive in all neoplastic cells, and staining for vimentin and S100 protein was negative. The cytomorphologic and immunohistochemical features of this tumor are similar to those seen in tumors in women, hence enabling the diagnosis of a rare case of primary secretory carcinoma of the canine mammary gland.     

Histopathologic lesions of diabetes mellitus in a domestic ferret

A 2-year-did ferret was referred with a diagnosis of diabetes mellitus. The animal died despite insulin therapy and was submitted for necropsy. Light microscopic examination revealed a mild hepatic lipidosis and pancreatic lesions consisting of a diffuse vacuolation of the Langerhans' islet cells with a periodic acid-Schiff positive material compatible with glycogen.     

Gynecomastia and mammary gland adenocarcinoma in a Nubian buck.

A 6-year-old Nubian buck was presented for bilateral mammary gland enlargement. Gynecomastia and mastitis were diagnosed, and bilateral mastectomy was performed. Histological examination showed mammary adenocarcinoma, active lactation, hyperplasia, and abscessation. Karyotyping showed a normal male. Clinical, therapeutic, etiologic, and epidemiologic aspects of gynecomastia and mammary gland adenocarcinoma are discussed.     

Immunity in the mammary gland.

The ruminant mammary gland is an extremely important economic organ in that it provides a major nutrition source for a significant portion of the world's human population. The ruminant mammary gland is also responsible for providing protective immunity to neonates and for defending itself from invading pathogens. A wide array of humoral and cellular immune mechanisms are present in the mammary gland and actively participate in providing immunity to newborns and the mammary gland per se. The acute inflammatory response is essential in determining the outcome of intramammary challenge, and factors affecting innate and adaptive immunity in the context of mammary health are reviewed in detail. The ruminant mammary gland is also unique in that lymphocyte trafficking, which is essential to adaptive immunity, is shared with the peripheral immune system rather than the common mucosal immune system.