The histogenesis of clear cell adenocarcinoma of the lower urinary tract. Case series and review of the literature.

Clear cell adenocarcinoma of the lower urinary tract is a rare neoplasm whose histogenesis has not been thoroughly investigated. We have examined six specimens of clear cell adenocarcinomas collected from three institutions using histological, histochemical, and immunohistochemical techniques. Results indicate that almost all clear cell adenocarcinomas of this region express morphological and antigenic features, suggesting müllerian differentiation, and that müllerian differentiation is not a feature of either nonclear cell adenocarcinomas or normal female paraurethral glands. Including the authors' six specimens, 46 specimens have been reported in the available English literature. The accumulated experience confirms the initial impression that these tumors develop predominantly in the urethras of women and occur over a wide age range. Despite high stage at diagnosis, most patients have been alive with no evidence of disease when reported, a prognosis that seems to apply regardless of length of follow-up.