Background: Malignant transformation to endometriosis is a well documented phenomenon that occurs most commonly in the ovaries with cancer arising in extra-ovarian endometriosis being a rare event.
Methods: A retrospective clinical-pathological evaluation of eleven cases with malignant tumors arising in endometriosis was performed to evaluate the prognostic impact of various factors. Nuclear DNA content (ploidy) was assessed through flow cytometric study.
Results: Ovarian origin was identified in eight cases and three were associated with extra-ovarian endometriosis. Histologic type was endometrioid carcinoma in ten patients. The eleventh case had high grade endometrial stromal sarcoma. All tumors were diploid with no relation to stage, grade, or clinical outcome. The S-phase fraction (SPF) was analyzed in nine patients and no correlation could be demonstrated with any histologic parameters or clinical outcome.
Conclusions: The DNA content seems to have no association with the classical prognostic parameters in these cases.