MRI of uterine leiomyosarcoma

We report a case of a patient with uterine leiomyosarcoma. At MR imaging, the patient was found to have a bilobed uterine mass with two components. While the caudal portion of the mass had the MRI appearance of a simple leiomyoma, the cephalad component showed atypical degeneration with an irregular contour. Malignant degeneration of a leiomyoma was confirmed by operative and histologic examination. We conclude that malignant degeneration should be considered on MR images of any degenerated leiomyoma showing an irregular contour.