Imaging in gynecological disease (22): clinical and ultrasound characteristics of ovarian embryonal carcinomas, non‐gestational choriocarcinomas and malignant mixed germ cell tumors

Objective: To describe the clinical and ultrasound characteristics of three types of rare malignant ovarian germ cell tumor: embryonal carcinoma, non-gestational choriocarcinoma and malignant mixed germ cell tumor. Methods: This was a retrospective multicenter study. From the International Ovarian Tumor Analysis (IOTA) database, we identified patients with a histological diagnosis of ovarian embryonal carcinoma, non-gestational choriocarcinoma or malignant mixed germ cell tumor, who had undergone preoperative ultrasound examination by an experienced ultrasound examiner between 2000 and 2020. Additional patients with the same histology were identified from the databases of the departments of gynecological oncology in the participating centers. All tumors were described using IOTA terminology. Three examiners reviewed all available ultrasound images and described them using pattern recognition. Results: One patient with embryonal carcinoma, five patients with non-gestational ovarian choriocarcinoma and seven patients with ovarian malignant mixed germ cell tumor (six primary tumors and one recurrence) were identified. Seven patients were included in the IOTA studies and six patients were examined outside of the IOTA studies. The median age at diagnosis was 26 (range, 14–77) years. Beta-human chorionic gonadotropin levels were highest in non-gestational choriocarcinomas and alpha-fetoprotein levels were highest in malignant mixed germ cell tumors. Most tumors were International Federation of Gynecology and Obstetrics (FIGO) Stage I (9/12 (75.0%)). All tumors were unilateral, and the median largest diameter was 129 (range, 38–216) mm. Of the tumors, 11/13 (84.6%) were solid and 2/13 (15.4%) were multilocular-solid; 9/13 (69.2%) manifested abundant vascularization on color Doppler examination. Using pattern recognition, the typical ultrasound appearance was a large solid tumor with inhomogeneous echogenicity of the solid tissue and often dispersed cysts which, in most cases, were small and irregular. Some tumors had smooth contours while others had irregular contours. Conclusions: A unilateral, large solid tumor with inhomogeneous echogenicity of the solid tissue and with dispersed small cystic areas in a young woman should raise the suspicion of a rare malignant germ cell tumor. This suspicion can guide the clinician to test tumor markers specific for malignant germ cell tumors