Single case report of prostate adenocarcinoma in a dog castrated three months previously. Morphological, biochemical, and endocrine determinations.

During the course of another investigation, three dogs had been castrated 3 months previously. Upon completion of the experiment, it was discovered that one dog presented a spontaneous prostatic adenocarcinoma of intraalveolar proliferative type at histology. Prostate weight of this dog before castration was estimated to be 22 g by tridimensional measurement at laparotomy and remained relatively constant (19 g) 3 months after castration. These results indicate that if regression had occurred in some cell populations (androgen-dependent) it was only partial and masked by growth of androgen-independent cells. Analysis of 12 individual steroids in peripheral blood and in prostatic tissue attested of a normal adrenal secretory activity. A series of 15 hydrolytic enzymes along with receptors for androgen, estrogen, and progesterone, were determined in prostatic tissue obtained at sacrifice. Enzymatic activities were those of typical epithelial cells, and most of them remained relatively high despite low levels of circulating testosterone. However, two markers of androgen action in dog prostate, acid phosphatase and arginine esterase, were significantly reduced. Receptor levels were similar to those of castrated animals. Thus, cancer cells had probably retained some androgen sensitivity.