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 endometriosis-associated 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.