Imaging diagnosis of pregnancy-associated ovarian tumors

Objective: To investigate the possibility of prediction of the histological type of ovarian tumors by preoperative imaging in patients had undergone surgery for pregnancy-associated ovarian tumors.Methods: Maternal ovarian tumor was detected by ultrasonography (USG) examination and magnetic resonance image (MRI) and operation was performed in 18 pregnant women.In 18 cases, collected medical records, USG/MRI and pathologic findings were analyzed retrospectively.Results: Histopathological diagnoses were parovarian cyst, simple cyst, mucinous cystadenoma, a combination of mucinous cystadenoma and mature cystic teratoma, mature cystic teratoma, hemorrhagic lutein cyst, immature teratoma (Grade1), a combination of mucinous cystadenocarcinoma and mature cystic teratoma. The rate of agreement between the tissue pattern predicted by USG and the histopathological diagnosis was 25%. Matching rate for dermoid cysts was 37.3%. Immature teratoma (G1) could not be predicted preoperatively, but a combination of mucinous cystadenocarcinoma (G1) and mature cystic teratoma was diagnosed as ovarian cancer and a low malignant potential case by some gynecologists. MRI was useful for the diagnosis of dermoid cyst. On the other hand, it was quite difficult to diagnose the tumors as malignant by MRI.Conclusions: USG can make images at a given cross-section in real-time, and follow the time course of their changes. On the other hand, MRI may display excellent tissue contrast to target tissues and delineate more accurate morphological changes. The combined use of USG and MRI may further improve the diagnosis of ovarian tumors