Parasitic leiomyoma of the small bowel mesentery mimicking a gastrointestinal stromal tumor: a case report.

Background: Parasitic leiomyoma is a rare subtype of uterine leiomyoma located outside the uterus, often deriving its blood supply from adjacent organs. With the popularization of laparoscopic surgery, reports of iatrogenic parasitic leiomyoma (IPL) as a long-term complication of unconfined morcellation have been increasingly frequent. These tumors may mimic gastrointestinal tumors, posing a significant challenge to clinical diagnosis. Case description: A 38-year-old female presented with periumbilical pain accompanied by abdominal distension for 1 week. The patient had a history of laparoscopic uterine myomectomy 6 years ago. Abdominal CT suggested a mass in the small bowel mesentery. This lesion was initially suspected to be a small bowel gastrointestinal stromal tumor (GIST). The patient underwent laparoscopy, during which a solid tumor attached to the small bowel mesentery with an independent vascular pedicle was found. The mass was surgically resected, and histopathological examination confirmed it as a parasitic uterine leiomyoma with red degeneration. The patient recovered smoothly after surgery. Conclusion: This case highlights the difficulty in differentiating parasitic uterine leiomyomas from gastrointestinal tumors based solely on imaging features. For patients with a history of uterine surgery (particularly those who underwent laparoscopic myomectomy with a history of morcellation), parasitic uterine leiomyoma should be included in the differential diagnosis if an abdominal mass is detected. Early recognition helps to avoid unnecessary extensive bowel resection, thereby preventing unnecessary radical resection.