Perianal gland adenocarcinoma with metastases in dog: A case report

Canine perianal adenocarcinoma is a malignant tumourthat occurs mainly in old dogs and arises from the modified sebaceous perianal glands, often referred to as ‘‘hepatoid glands’’ because of their morphological resemblance to hepatocytes. The present communication reports a perianal gland carcinoma with metastases to various organs. ALabrador bitch was presented for postmortem examination with the history thatthe animal being euthanized as it was seriously ill and not responding to any therapy. Grossly, the perianal gland was enlarged and bulging and covered by intact skin. Large tumour mass about 400g and firm in consistency was observed in the perianal region, but covered by skin. The retroperitoneal and iliac lymph nodes, liver, lungs and their associated lymph nodes also showed metastatic nodular tumour masses. Histologically, the tumor consisted of single cell type undifferentiated reserve cells with hyper chromatic nuclei, prominent nucleoli, little cytoplasm and revealed a few mitotic figures. These cells were closely packed with little interstitial connective tissue. The necrosis was also noticed at the centre of the each lobule. Peripherally, there was infiltration of inflammatory cells and focal haemorrhages. Similar type of undifferentiated reserve cells was observed as solid pattern in the lungs and lymph nodes. A rare unusually enlarged perianal gland carcinoma with metastases in lung, liver and lymph nodes has been described.