Pathology of spontaneous mucinous ovarian adenocarcinoma in a gramasree hen

Ovarian adenocarcinomas are highly malignant tumours arising from the ovarian surface epithelium, which is characterized by widely varied histomorphology. A dead three-year-old female Gramasree layer bird was brought for postmortem examination. An enlarged nodular ovarian mass with smooth-surfaced coalescing small nodules was present in the coelomic cavity without the involvement of oviduct. Similar individual nodules were seen attached to the serosa of the duodenum. Microscopically, the ovarian nodules were well-encapsulated structures containing pleomorphic neoplastic epithelial cells in diffuse, irregular tubulo-acinar patterns supported by a fibrovascular stroma. Nodules of intestinal serosa also showed neoplastic epithelial cells in the tubulo-acinar pattern. Periodic Acid Schiff stain and intense blue with Alcian blue stain confirmed that a mucinous substance was present inside the tubules of neoplastic growth. Immunohistochemically, tumour cells revealed positive immunoreactivity for pancytokeratin. Based on the gross, cytological, histopathological, and immunohistochemical examinations, the case was diagnosed as mucinous ovarian adenocarcinoma with transcoelomic metastasis.