Imaging features of growing teratoma syndrome following a malignant ovarian germ cell tumor

OBJECTIVE: To access imaging findings of growing teratoma syndrome (GTS), which is a rare complication of malignant ovarian germ cell tumor (GCT) after chemotherapy. METHODS: Five patients met the criteria for GTS. Computed tomography and magnetic resonance images were retrospectively reviewed by 2 radiologists in consensus for margin, attenuation, and the presence of gross fat or calcification of GTS lesions, which were compared with primary GCTs regarding tumor composition. RESULTS: Growing teratoma syndrome lesions were characterized as follows: poorly circumscribed, diffuse peritoneal masses in 2 patients; well-circumscribed, localized peritoneal masses in 1 patient, and ovarian masses in 2 patients. Features more noticeable in GTS lesions were more prominent fatty components in 4 patients and purely cystic lesion in 1 patient. CONCLUSIONS: Growing teratoma syndrome can be manifested as intraperitoneal masses with an increased fatty or cystic component. Radiologists should consider GTS when there are such masses on follow-up imaging studies in patients with malignant ovarian GCT.