Lipoleiomyoma: a potential mimic of an ovarian dermoid cyst on MRI-a case report.

Uterine lipoleiomyomas are rare variants of uterine leiomyomas which is composed of adipocytes and smooth muscle cells. In this report, we describe the case of a 39-year-old patient who presented with persistent, isolated pelvic pain. Ultrasonography showed an oval, well-defined left ovarian mass. Computed tomography (CT) scanning showed a predominantly-fatty mass with tissular components, no calcifications and heterogeneously enhanced after injection, suggesting initially a mature teratoma. Magnetic resonance imaging (MRI) findings revealed a latero-uterine mass, suggesting the presence of a left ovarian dermoid cyst with a potentially-malignant fleshy component. A subsequent pathology report revealed a lipoleiomyoma with cartilaginous metaplasia. Most notably, despite the fatty nature of the tumour and the use of MRI, the pedunculated appearance of the lipoleiomyoma observed intraoperatively mimicked a dermoid tumour even on imaging. Improved understanding of leiomyoma variants and secondary degenerative changes can help prevent misdiagnosis.