Endocervicosis of the urinary bladder. A report of six cases of a benign müllerian lesion that may mimic adenocarcinoma.

Six tumor-like glandular lesions characterized by a prominent component of endocervical-type epithelium involved the wall of the urinary bladder in women of reproductive age (31 to 44 years; mean, 37). All of the lesions posed problems in histologic diagnosis; indeed, a diagnosis of adenocarcinoma was initially rendered in three cases. Five patients presented with bladder symptoms, including--alone or in combination--suprapubic pain, dysuria, frequency, and hematuria. There was catamenial exacerbation of the symptoms in one case. The sixth patient--the only one with documented pelvic endometriosis--presented with dysmenorrhea, dyspareunia, and lower abdominal tenderness. In each patient, a mass that ranged from 2 to 5 cm in maximum dimension was typically located in the posterior wall or posterior dome of the urinary bladder. A partial cystectomy (five cases) or transurethral resection (one case) was performed. In one patient, extravesical pelvic soft tissue was involved, precluding complete resection of the lesion. Microscopic examination revealed extensive involvement of the bladder wall by irregularly disposed, benign-appearing, or mildly atypical endocervical-type glands, some of which were cystically dilated. Other findings included occasional ciliated cells, typically interspersed with the endocervical-type cells (four cases), a minor component of endometrioid glands (three cases), and glands lined by nonspecific cuboidal or flattened cells with eosinophilic cytoplasm (all cases). Some of the glands were surrounded only by the smooth muscle of the muscularis propria, but in other areas, the periglandular tissue was fibrous or edematous. In three cases, rare glands were surrounded by thin rims of endometriotic stroma. Gland rupture resulted in stromal extravasation of mucin in all cases and was a prominent feature in one. All patients had uneventful postoperative follow-up periods ranging from 1.5 to 14 years. The findings indicate that these bladder lesions are müllerian in nature and represent examples of endocervicosis, the mucinous analogue of endometriosis. Awareness of the lesion, which with one possible exception is hitherto undescribed in the bladder, and attention to its typical histologic features should facilitate its crucial distinction from adenocarcinoma.