Primary Unilateral Small Cell Neuroendocrine Carcinoma of the Kidney in a Dog

Primary small cell carcinomas are rare in domestic animals. A mass measuring 15 × 20 × 9 cm was detected in the left abdominal cavity of a 7.5-year-old female golden retriever. The cut surface of the excised mass showed a tumour replacing the left kidney. Microscopically, the mass was composed of polymorphic, small basophilic cells with a high nuclear to cytoplasmic ratio and round, oval or short slender fusiform nuclei with condensed or finely granular chromatin, absent or inconspicuous nucleoli, and scant, faintly eosinophilic cytoplasm with poorly defined cytoplasmic borders. Immunohistochemically, most of the neoplastic cells were immunoreactive for thyroid transcription factor 1 and CD56, moderately positive for vimentin and weakly or sparsely labelled for chromogranin A, synaptophysin, Wilms' tumour 1 protein, neuron-specific enolase, pan-cytokeratin (CK) AE1/AE3 and epithelial membrane antigen. The tumour cells were negative for glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1, CK7, CK20, CD3, CD45 and CD99. These findings indicated a neuroendocrine origin of the tumour. To the best of author's knowledge, this is the first report of a small cell neuroendocrine carcinoma originating as a primary tumour in the kidney of a dog.

Hepatic neuroendocrine carcinoma with metastases to the lymph nodes in a sika deer (Cervus nippon yakushimae)

A 26-year and 6-month-old male sika deer that was kept at the Showa Park, Tokyo, Japan, collapsed and died of severe disease wasting and severe tabefaction. Grossly, numerous masses, 0.3–1.0 cm diameter, were dispersed throughout the liver. The multiple masses were composed of tumor cells, which had hypochromatic nuclei and abundant faintly eosinophilic cytoplasm, arranged in nests of various sizes. Immunohistochemically, tumor cells were positive for cytokeratin, chromogranin A, synaptophysin and gastrin. Ultrastructurally, the cytoplasm of the tumor cells contained abundant membrane-bound electron-dense granules. A metastatic lesion was observed in the renal, hepatic and pancreatic lymph nodes. On the basis of these findings, this tumor was diagnosed as a neuroendocrine carcinoma with metastases to the lymph nodes.

A case of feline primary duodenal carcinoid with intestinal hemorrhage

A 15-year-old neutered male Persian cat was presented with recurrent hematemesis and melena. Abdominal ultrasonography and computed tomography revealed a mass in the proximal descending duodenal wall. Endoscopic examination revealed hemorrhage on the luminal side of the mass. Fine-needle aspiration of the mass was performed. Microscopic analysis revealed a cluster of cells with oval nuclei and indistinct cell borders, suggesting a neoplastic disease of neuroendocrine origin. The mass located near the major duodenal papilla was partially resected, and the bleeding was stopped by cauterization. However, the surgical procedures could not control the hemorrhage from the tumor mass, and the cat died of severe anemia. Immunohistopathological analysis revealed that the tumor was a duodenal carcinoid.

Pancreatic neuroendocrine carcinoma with exocrine differentiation in a young cat

A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells. The small cells were arranged in nests of various sizes, which were separated by thin fibrous stroma, and had small, round, hyperchromatic nuclei, scant cytoplasm containing argyrophilic granules, and often formed rosettes. The epithelial cells formed luminal structures. Metastases were observed in the liver, greater omentum, and pancreatic, gastric, pulmonary, and mediastinal lymph nodes. Immunohistochemical examination revealed that the small cells were positive for vimentin, neuron-specific enolase, chromogranin A, cytokeratin (CK) AE1/AE3, and trypsin, whereas the epithelial cells were positive for AE1/AE3, trypsin, CK19, and nestin. Ultrastructurally, the small cells contained abundant electron-dense granules, ~200 nm diameter, whereas the epithelial cells had apical microvilli and numerous zymogen granules, ~300 nm diameter. These findings indicated that the tumor was a pancreatic neuroendocrine carcinoma with exocrine differentiation and systemic metastases.

A feline case of hepatic neuroendocrine carcinoma with gastrin immunoreactivity

A 5-year-old castrated Japanese domestic cat was presented with persistent vomiting. Ultrasound examinations revealed many masses only in the liver, and the fine needle aspiration was performed. Cytologically, polygonal or oval shaped tumor cells forming rosette and cord-like patterns were demonstrated, and then, the hepatic lesions were diagnosed as neuroendocrine carcinoma tentatively. The cat died one month after admission and was necropsied. Histopathologically, the tumor cells of the hepatic mass were arranged in typical rosette and cord-like structures. They were considerably uniform in size with hyperchromatic round nuclei and eosinophilic cytoplasm. Most of tumor cells were immunopositive for chromogranin A, and some were positive for gastrin. The findings indicate the possibility that the present case was a gastrin-producing neuroendocrine carcinoma.