Objective: We present the MR imaging appearance of three cases of pathologically proven placental site trophoblastic tumor (PSTT), a potentially malignant but rare form of gestational trophoblastic disease.
Conclusion: In our series, PSTT presented as myometrial masses that were isointense to healthy myometrium on T1-weighted images and isointense to slightly hyperintense on T2-weighted images. No associated cystic spaces or prominent blood vessels were identified. These MR findings are not specific, and the diagnosis of PSTT is made from biopsy specimen. In two cases, PSTT was invisible sonographically, and accurate localization with MR imaging allowed the patients to be treated with hysterotomy rather than with hysterectomy.