Background: To investigate (i) what determines the histologic differences seen among female urethral diverticular cancers and (ii) the possible embryologic origin of the female paraurethral duct, we performed a distribution analysis of endocrine cells and a comparative study of tissue-associated antigens in the female paraurethral duct.
Methods: Six human female urethras were obtained from surgical and autopsy cases including two cases of urethral diverticular cancer (columnar/mucinous type adenocarcinoma). The urethral and paraurethral epithelia were examined histologically and immunohistochemically.
Results: Immunoreactive endocrine cells predominated and carcinoembryonic antigen (CEA) was strongly expressed in the larger portion of the paraurethral duct close to the urethral lumen. Conversely, prostate-specific antigen and prostatic acid phosphatase were positive only in the smaller distal duct. In two cases of adenocarcinoma including endocrine cells, cancer cells were strongly positive for CEA.
Conclusions: This study suggests that the proximal and distal parts of the paraurethral duct have different histologic characteristics and that the pathologic differences seen among female diverticular cancers may result from their cancer-genesis from different parts of the paraurethral duct.