"Endometrial" adenocarcinoma of the prostate: a distinctive tumor of probable prostatic duct origin.

A so-called "endometrial" adenocarcinoma of the prostate has been studied by light and electron microscopy, and by histochemical techniques. The previously proposed utricular origin and estrogen dependence of such tumors is questioned. Strong acid phosphatase staining, and the ultrastructural demonstration of multivacuolated, lipid, and lysosome-containing tumor cells, suggest a prostatic ductal origin for this type of carcinoma despite the histologic similarity to carcinoma of the endometrium.