Intraperitoneal Parasitic Leiomyoma With Torsion

Extrauterine leiomyomas are rare histologically benign tumors. These usually arise in the pelvis and may develop an auxiliary blood supply and become parasitic. Parasitic leiomyoma occurring in patients without prior abdominal or pelvic surgery is extremely rare, with fewer than 30 reported cases in the literature. We report a rare case of parasitic leiomyoma in a 41-year-old woman with no uterine leiomyoma or history of previous surgery. She presented with recurrent lower abdominal pain of one-month duration, and ultrasound revealed a solid, heterogeneously hypoechoic lesion in the hypogastrium. On MRI, the lesion was intraperitoneal and demonstrated a thrombosed vascular pedicle. Laparotomy showed a solid, intraperitoneal mass, adherent to the omentum and anterior parietal peritoneum. Multiple feeding vessels were seen arising from the greater omentum and mesentery with a tortuous, thrombosed vascular pedicle. Histopathology showed interlacing fascicles and bundles of spindle-shaped smooth muscle fibers with cigar-shaped nuclei, consistent with leiomyoma. Imaging plays a vital role in characterizing and differentiating leiomyomas from other masses and in guiding appropriate surgical intervention.