Ultrasound Findings andO‐RADSMalignancy Risk Stratification of Ovarian Collision Tumors
Objectives
To describe the ultrasonographic signs of ovarian collision tumors and evaluate the malignancy risk using the O‐RADS system.
Methods
This was a retrospective analysis of 25 ovarian collision tumors from 8739 patients between May 2010 and January 2020. All clinical characteristics, ultrasound images, and histological findings were collected and analyzed. Using the O‐RADS lexicon descriptors, the O‐RADS score was determined by two senior doctors. Lesions with O‐RADS scores of 1 to 3 were classified as benign tumors, and lesions with O‐RADS scores of 4 to 5 were classified as malignant tumors.
Results
The mean age of the 25 patients was 30.4 years. Histological findings showed that all tumors were a combination of mature cystic teratomas and cystadenomas/cystadenocarcinomas. There were 11 benign tumors of O‐RADS 2 or 3, including 3 uniocular cysts, 3 dermoid cysts, and 5 dermoid cysts with an anechoic fluid cavity. There were 12 benign tumors of O‐RADS 4, including 3 uniocular–multilocular cysts with solid components, 2 multilocular cysts with irregular walls, and 8 multilocular cysts with dermoid sacs. One borderline tumor of O‐RADS 4 was a multilocular cyst with irregular septation. One malignant tumor of O‐RADS 5 was a multilocular cystic tumor with solid components and ascites.
Conclusions
The most common ovarian collision tumor was the coexistence of a mature cystic teratoma and a cystadenoma. The O‐RADS system was able to sensitively detect malignant tumors in this series. A typical dermoid cyst with an anechoic cavity or a multilocular cyst with a dermoid sac may signify a benign collision tumor.