Decidualization of ovarian endometriosis during pregnancy mimicking malignancy: report of three cases with a literature review

Abstract

Background: Intracystic papillary excrescence is a characteristic morphological feature of ovarian malignancy. A few recent reports have demonstrated that ovarian endometriotic cysts, undergoing decidualization during pregnancy, occasionally show excrescence, necessitating surgery during pregnancy; however, this phenomenon is not well recognized among clinicians.

Cases: Three pregnant women with decidualized ovarian endometriosis showed excrescence. Both ultrasound and magnetic resonance imaging (MRI) preoperatively suggested the presence of underlying ovarian endometriotic cysts in 2 women, but not in the other. Intracystic papillary excrescence prompted us to perform laparotomy at 14, 14, and 19 weeks of pregnancy, respectively, with 1 woman aborting in the 21st week, and with 2 delivering healthy term infants. Histological examination confirmed the diagnosis of decidualized ovarian endometriotic cysts in all 3 patients.

Conclusions: We provide the first report of pregnant women in whom excrescence occurred from ovarian endometriotic cysts without preoperative evidence. Decidualized ovarian endometriosis, even without preoperative morphological features of endometriosis, should be added to the differential diagnosis of ovarian malignancy during pregnancy.