Submucosal endocervicosis of the bladder: an ectopic, glandular structure of Müllerian origin.

Endocervicosis of the bladder is a rare, benign variant of endometriosis. The lesions are characterized by ectopic, glandular structures of Müllerian origin with intracytoplasmic mucin production. During placement of a ureteral stent, a cystic tumor in the posterior bladder wall was discovered in a 47-year-old woman with nephroureterolithiasis. CT and MRI revealed a 5 x 1.6 cm(2) mass in the posterior bladder wall protruding into the lumen of the bladder. Urine culture and cytological analyses showed no malignancy. Transurethral biopsy of the tumor confirmed the diagnosis of endocervicosis. Complete transurethral resection was rejected due to the absence of symptoms and the benign condition of the lesion.