Gastric Neuroendocrine Carcinoma in a Dog

Abstract

A gastric biopsy specimen from a 14-year-old Yorkshire terrier was analysed using light microscopy, immunohisto-chemistry and transmission electron microscopy. The biopsies were obtained from a 3 × 3 × 4 cm mass located at the gastric cardia. Light microscopy revealed solid nests and sheets of tumour cells separated by abundant fibrovascular stroma in all gastric layers. The tumour cells were monomorphic, with eosinophilic cytoplasm and demonstrated palisading at the periphery. Nuclei were round to oval with densely packed chromatin and inconspicuous nucleoli. The tumour cells immunohistochemically stained strongly positive for chromogranin A, synaptophysin, and pan-cytokeratin. Electron microscopy revealed electron dense neurosecretory granules of 100 -150 nm in diameter. Metastases were found in regional lymph nodes. Gastric neuroendocrine carcinoma was diagnosed, according to the histological, immu-nohistochemical and electron microscopic features.