Parasitic Myomas: Report of the Largest Case Series

Abstract

Study Objective: To report the largest case series of parasitic myomas in the medical literature, and an examination of etiologies, associations, and risk factors. Design: Descriptive retrospective study. Setting: Private gynecologic surgery practice at tertiary care center. Patients: 13 patients with the diagnosis of parasitic myoma were identified in a prospective registry of surgical cases performed between August 2000 and April 2008. Intervention: All patients underwent operative laparoscopy. Intraoperative findings were correlated with pathologic findings. Demographic data, previous medical conditions, previous abdominal or pelvic surgery, prior use of morcellation, pathology, postoperative course, and follow up were systematically retrieved from patient medical records. Pathologic confirmation of all specimens was obtained. Measurements and Main Results: Laparoscopic evaluation confirmed the presence of intraperitoneal and retroperitoneal myomas distinct from the uterus in 13 patients. Ten of the 13 patients had prior abdominal surgery. Eight patients had prior morcellation procedures; six performed laparoscopically, two performed by laparotomy. Three patients had multiple parasitic myomas, all of whom had a history of laparoscopic myomectomy with morcellation. The majority (13/17) of myomas were found in the pelvis including two retroperitoneal myomas, and one embedded in the bladder. 8/17 myomas were found along the gastrointestinal tract, and 3/17 were found in the upper abdomen. Conclusion: Parasitic myomas may occur spontaneously as pedunculated subserosal myomas lose their uterine blood supply and parasitize to other organs. However, this series supports what the literature has suggested; more parasitic myomas may be iatrogenically created after prior surgery, particularly surgery using morcellation techniques. With increasing rates of laparoscopic procedures, surgeons should be aware of the potential for iatrogenic parasitic myoma formation, their likely increasing frequency, and intraoperative precautions to minimize occurrence.