An Intraluminal Parasitic Leiomyoma of the Sigmoid Colon and Potential Pathogenetic Mechanisms.

Uterine leiomyomas are the most common benign tumor of the female pelvis. Parasitic leiomyomas are an extremely rare entity of leiomyoma occurrence found at extrauterine sites. They are mostly diagnosed in patients with a history of gynecologic procedures and morcellators use during laparoscopic leiomyoma resection. Here we present an extraordinary case of an intraluminal leiomyoma of the sigmoid colon that was incidentally discovered during total abdominal hysterectomy and bilateral salpingo-oophorectomy, performed due to leiomyomatous uterus in a female patient with no history of previous gynecologic operations. Potential pathogenetic mechanisms that can explain the co-occurrence of leiomyomas in the uterus and the sigmoid colon are also reviewed and include genetic predisposition, the stem cell theory of leiomyomas formation, and lymphatic and vascular spread.