Neoplasms resembling ovarian common epithelial-type tumors, including clear
cell adenocarcinomas, rarely occur in the lower urinary tract of men. When
they do, they develop in the urethra or urinary bladder, We report a case
of such a tumor arising within the prostate of a 47-year-old man. The tumor
was a cystic mass in the left posterolateral region of the prostate. Histo
logically, the tumor was chiefly composed of tubulocystic and papillary gla
nds lined by glycogen-rich, cuboidal or hobnail cells with clear to eosinop
hilic cytoplasm. The tumor cells were strongly positive for pan-cytokeratin
, low molecular weight cytokeratin, and epithelial membrane antigen, and fo
cally positive for high molecular weight keratin. The tumor did not immunoh
istochemically express prostate-specific antigen (PSA) and prostatic acid p
hosphatase. Serologically, the patient had increased levels of CA125 instea
d of PSA. The clinical as well as the pathologic features are consistent wi
th a clear cell adenocarcinoma as seen in the female genital tract rather t
han a typical prostatic adenocarcinoma.