Adenocarcinoma of the small intestine in a goat.

A case of intestinal adenocarcinoma is described in a 4-year-old dairy goat with progressive emaciation. At necropsy, a tumour was found in the middle part of the jejunum as an annular, firm white mass which resulted in stenosis and dilation of the intestine proximal to the lesion. Spread of the tumour, with thickening of the contiguous mesentery, and metastasis to the mesenteric lymph nodes were observed. Microscopically, the tumour was characterized by nests or sheets of mucin-rich cuboid or columnar epithelial cells, which formed irregular acinar structures that infiltrated all layers of the intestinal wall. In the mesentery, neoplastic cells were surrounded by an intense fibrous reaction. A diffuse inflammatory infiltrate of lymphocytes was observed both in the mesentery and in the intestinal layers. These findings are compared with those observed in sheep, in which this type of tumour occurs more frequently.