Endometriosis-associated extraovarian malignancies: A challenging question for the clinician and the pathologist

Endometriosis is an estrogen-dependent disease, which affects 10% of women in the reproductive age. Malignant transformation is an uncommon event, which affects approximately 0.7-2.5% of women, and, when it occurs, it involves ovarian and extraovarian sites in 75% and 25% of the cases, respectively. Endometriosis correlates with presentation of clear cell and endometrioid carcinoma of the ovary. Activation of phosphatidylinositol 3-kinase (PIK3) - protein kinase B (AKT) - mammalian target of rapamycin (mTOR) pathway, aberrant chromatin remodeling due to AT-rich interactive domain-containing protein 1A (ARID1A) mutation and inactivation of estrogen receptor-α signaling seem to play a major role in the carcinogenesis. To date, little data are available regarding endometriosisassociated extraovarian malignancies. The aim of the present study was to review the clinical, pathological and prognostic features of endometriosis-related neoplasms arising from extraovarian sites, with particular focus on intestinal malignancies, urinary tract malignancies and tumors arising from surgical scars.