Precursor Lesions of Cervical Clear Cell Carcinoma: Evidence For Origin From Tubo-Endometrial Metaplasia.

Cervical clear cell carcinoma (CCC) is an HPV-independent tumor historically associated with in-utero exposure to diethylstilboestrol. With the cessation of diethylstilboestro use, most contemporary cases are sporadic and of uncertain pathogenesis, with no established precursor lesion. Following the detection of 3 incidental "early" (FIGO stage IA1) cervical CCCs, all of which displayed adjacent tubo-endometrial metaplasia, we examined further cases, including resection specimens, of this tumor in an attempt to delineate potential precursors. We identified tubo-endometrial metaplasia in proximity to the tumor in 5 of 5 additional primary cervical CCCs, with some tubo-endometrial glands exhibiting subtle mild cytologic atypia. This observation adds to the sparse existing literature proposing tubo-endometrial metaplasia as a precursor to sporadic cervical CCC, with possible progression via an "atypical" transitional phase to malignancy. We also review the published literature regarding possible precursor lesions of primary cervical CCC.