Prostatic adenocarcinoma in a castrated dog.

Atypical prostatic adenocarcinoma was diagnosed in a castrated dog. The gland was of normal size, contrary to what has been reported in most other cases in dogs. Metastases were not seen, even though radiography suggested metastasis to the external iliac lymph nodes and histologic examination revealed the neoplasm to have a moderately malignant character. Even though hormones have been implicated as a cause of prostatic adenocarcinoma in man, the development of such a neoplasm in dogs castrated at an early age, as exemplified by this case, may cast doubt on that hypothesis.