OP24.07: Imaging of gynecological disease: clinical and ultrasound characteristics of decidualized endometriomas

To describe the clinical history and ultrasound findings in women with decidualized endometriomas. Women with a histological diagnosis of decidualized endometrioma during pregnancy who had undergone preoperative ultrasound examination were identified from the databases of 7 ultrasound centers. The tumors were characterized on the basis of ultrasound images, ultrasound reports and research protocols (when applicable) using the terms and definitions of the International Ovarian Tumor Analysis (IOTA) group. Of 18 patients identified, 17 were primigravid and 1 was multiparous. Median age was 33 years (range 20–43). Median gestational age at surgical removal of the decidualized endometrioma was 18 weeks, range 11–40. Seventeen patients (94%) were asymptomatic, one presented with pelvic pain. In 3 of the 18 patients a diagnosis of endometrioma had been made before pregnancy. The ultrasound examiner was uncertain in 10 (56%) cases and suggested a diagnosis of benignity in 11/18 (61%) cases, borderline in 3 (17%), invasive in 4 (22%) cases. Most decidualized endometriomas (16/18 cases, 89%) contained solid components, vascularized at power Doppler examination. Using pattern recognition most decidualized endometriomas (15/18, 83%) showed the presence of “rounded” papillary projections with a smooth contour. No patient had ascites. Rounded vascularized papillary projections with smooth contour within an ovarian cyst with ground glass echogenicity seems to be the landmark of decidualized endometrioma in pregnant patients.