Endocervicosis of the urinary bladder. Immunohistochemical comparative study between a new case and normal uterine endocervices.

Endocervicosis of the urinary bladder is a rare non-neoplastic condition characterized by endocervical-type glands deeply situated in the urinary bladder wall of women of reproductive age. We compared the immunohistochemical phenotype of a case of endocervicosis in a 35-year-old woman with four normal uterine endocervices. We tested antibodies known as reactive in the uterus and not mentioned or negative in the urothelium (HBME-1, estrogen receptor (ER), progesterone receptors (PR), DF3, Chromogranin). The proliferative index was assessed with MIB-1 antibody. Endocervicosis glands displayed stronger expression of HBME-1, ER and PR than normal endocervices, while the urothelium was negative. There was no difference in DF3 expression. The number of Chromogranin-positive cells was higher in endocervicosis than in the endocervices. The proliferative index was higher in the endocervicosis glands (15%) than in the normal endocervices (mean 3%), but was within the normal range established for endocervical glands. Our results confirm the endocervical nature of endocervicosis and constitute further arguments for the mullerian origin hypothesis. The only modestly increased proliferative index, as compared to endocervical malignancies, is consistent with a benign diagnosis.