Case report: cotyledonoid dissecting leiomyoma in a 49-year-old woman.

Background: Cotyledonoid dissecting leiomyoma (CDL) is much less common than typical leiomyoma. Macroscopically, it displays multinodular, exophytic, placenta-like cystic masses and extends into the broad ligament, pelvic cavity, and retroperitoneal space. The seemingly malignant gross appearance of the tumor has perplexed gynecologists and pathologists; microscopically, it has no malignant characteristics, such as atypical cells, a high mitotic index, or tumor necrosis. To date, only a few cases of CDL have been reported. Here, we report a case of CDL, highlighting its gross and histological appearance, and present a review of the literature. Case Description: A 49-year-old woman presented with a history of progressive constipation of 6 months' duration and a palpable left lower abdominal mass of 1 month's duration. Transvaginal ultrasound revealed a bulky uterus containing 2 subserosal fibroids measuring 9.9 cm × 6.9 cm × 6.3 cm and 8.1 cm × 6.6 cm × 6.8 cm, respectively. An abdominal modified radical hysterectomy and bilateral salpingo-oophorectomy was performed. An intraoperative frozen section showed an angioleiomyoma with edema. However, the postoperative paraffin section confirmed a diagnosis of CDL. No abnormalities were observed at the 6-month follow-up visit. Conclusions: Despite its seemingly malignant gross appearance, CDL, based on its microscopic appearance, is a rare benign tumor and has a favorable prognosis.