IntroductionLeiomyoma is the most frequent benign pathology in females and arises from uterine smooth muscle.AimWe present an uncommon example of a big, cystic-solid extra-uterine myoma that seemed on sonography and magnetic resonance imaging to be a primary malignant tumor.Case studyA woman was admitted to our hospital with a palpable abdominopelvic mass. Imaging studies described a large semisolid mass of 30 × 25 × 23 cm that filled the abdomen from the pelvis to the xiphoid process. Preoperatively, a primary malignant ovarian cancer or teratoma was identified.Results and discussionHistological analysis confirmed a leiomyoma with myxoid degeneration without any malignancy.ConclusionsThere is a high risk of malignancy in a giant uterus/mass and fast-growing myomas. For the treatment of large leiomyomas/large extra-uterine leiomyomas, a surgical approach is usually chosen. Myxoid leiomyoma of the broad ligament is very rare, its diagnosis remains histological to date like uterine myxoid leiomyoma. Malignancy should always be ruled out.