Magnetic Resonance Manifestations of Hyperreactio Luteinalis

Objective: Hyperreactio luteinalis (HL) is a rare benign physiological ovarian enlargement associated with gestational trophoblastic disease or pregnancy, and may mimic neoplasm. We evaluated magnetic resonance findings of HL to distinguish from neoplasm by using diffusion-weighted imaging with apparent diffusion coefficient (ADC) measurement. Methods: Magnetic resonance manifestations of 15 cases of HL in 8 women (mean age, 32 years) were retrospectively evaluated. Diffusion-weighted imaging (b = 0 and 800 seconds/mm2) was obtained in 11 cases of HL, and ADC was compared with that in solid portions of 18 ovarian cancers. Results: All cases of HL appeared as multilocular cystic masses with septations mimicking mucinous cystic tumors. Intervening ovarian stroma exhibited hyperintensity on diffusion-weighted imaging. The ADC in ovarian stroma in HL was significantly higher than that in solid portions of ovarian cancers. Conclusion: Ovarian stroma in HL may mimic solid tumorous components in mucinous tumors; however, high ADC reflecting edematous, luteinized stroma may be helpful for the diagnosis of HL.