Cutaneous metastases of prostatic adenocarcinoma in two dogs

Canine prostatic adenocarcinoma is an aggressive malignancy characterized by rapid growth, local invasiveness, and early metastatic spread. Metastases of prostatic cancer are generally diffuse at the time of diagnosis due to hematogenous or lymphatic spread and by direct exfoliation of neoplastic cells into the peritoneal cavity. Here we describe two dogs with prostatic adenocarcinoma and skin metastases. The first was a 12-year-old intact male German Shepherd dog that was presented with a history of chronic prostatic disease and multiple skin nodules that recently appeared on the ventral abdomen. The second was an 8-year-old intact male mixed breed dog that was referred for a neurologic examination because of a 1-month history of back pain and kyphosis of undefined origin. Cutaneous cytology of the first case was suggestive of carcinoma, and at necropsy, prostatic adenocarcinoma with metastases to the skin, spleen, liver, pancreas, kidneys, and lungs were found. In the second case, a computed tomographic examination revealed a prostatic neoplasm with inguinal, subcutaneous, and cutaneous nodular metastases. Cytology and histopathology were suggestive of primary prostatic adenocarcinoma with cutaneous and subcutaneous metastases. To the authors' knowledge, these are the first reported cases of prostatic adenocarcinoma skin metastases in dogs with cytologic descriptions.