Utility of trichrome and reticulin stains in the diagnosis of superficial endometriosis of the uterine cervix.

Superficial endometriosis of the uterine cervix is a not uncommon lesion and the cells on the cervicovaginal smear shed from it can be easily mistaken for cervical glandular intraepithelial neoplasia (CGIN). The correct diagnosis can not always be easily made on H&E stained tissue sections unless it is suspected. The endometriotic stroma is often misinterpreted as stromal hypercellularity or postinflammatory fibrosis following erosion or ulceration of the cervical mucosa. Moreover, the endometriotic glands may resemble tubo-endometrioid metaplasia of the endocervical glands. This article describes the utility of trichrome and reticulin stains in the diagnosis of superficial cervical endometriosis. The absence of abundant thick collagen bundles and the investment of individual stromal cells by a fine reticulin network within the endometriotic foci are characteristic histologic features. These findings are not observed in the surrounding normal cervical stroma nor in the usual conditions in the differential diagnosis.