Cotyledonoid Dissecting Leiomyoma of the Uterus with Intravascular Luminal Growth: A Case Study

Here, we report the case of a 43-year-old female who was diagnosed with a cotyledonoid dissecting leiomyoma (CDL) of the uterus. CDL is a recently described and extremely rare variant of a benign leiomyoma that can grossly masquerade as a malignancy. The 13-cm sized tumor was located primarily on the extrauterine surface as an intrauterine continuity, which showed dark red, congested, bulbous protuberances. It was multinodular appearance, encasing the bilateral adnexae and the left iliac vein. Microscopically, the nodules were separated by extensive hydropic degeneration. The nodules were composed of cigar-shaped spindle cells with no mitosis, cellular pleomorphism or coagulation necrosis. They also showed an intravascular luminal growth pattern. CDL with intravascular growth was diagnosed after excluding intravascular leiomyomatosis, disseminated peritoneal leiomyomatosis, and benign metastasizing leiomyoma. The present case is the second reported case of CDL in Korea. Recognition of this rare and bizarre, malignancy-mimicking leiomyoma is crucial to prevent inappropriate treatment.