Ovarian masses with papillary projections diagnosed and removed during pregnancy: ultrasound features and histological diagnoses

OBJECTIVES: To elucidate if there are any ultrasound features that can be used to discriminate between benign and malignant cysts with papillary projections but no other solid components in pregnant women. METHODS: Thirty-four women with an ultrasound diagnosis of an ovarian cyst with papillary projections but no other solid components that had been surgically removed during pregnancy were identified from the databases of four ultrasound units. Some clinical and ultrasound information had been collected prospectively. Missing information was obtained retrospectively from ultrasound images, ultrasound reports and patient records. Using the prospectively and retrospectively collected data, the ultrasound appearance of the tumors was described using the terms and definitions of the International Ovarian Tumor Analysis (IOTA) group. The ultrasound characteristics were compared with the histological diagnosis. RESULTS: Nine-teen (56%) lesions were benign (16 decidualized endometriomas, one cystadenofibroma, one simple cyst, one struma ovarii), 12 (35%) borderline tumors, three (9%) primary invasive tumors (two immature teratomas, one endometroid cystadenocarcinoma). The contour of the papillations was smooth in 79% (15/19) of the benign tumors versus in 27% (4/15) of the malignant ones (P = 0.002), ground glass echogenicity of cyst fluid was present in 74% (14/19) versus in 13% (2/15) (P = 0.0005). All ovarian masses with smooth contour of the papillations and ground glass cyst content (n = 12) were decidualized endometriomas. The papillary projections were vascularized and the color score was 3 or 4 in 87% (14/16) of decidualized endometriomas versus in 41% (5/12) of borderline tumors (P = 0.017). CONCLUSIONS: During pregnancy cysts with papillations with smooth contour and ground glass echogenicity of cyst fluid on ultrasound are most likely to be decidualized endometriomas. Papillations with irregular contour and anechoic or low level echogenicity of cyst fluid suggest borderline malignancy.