We report a case of spontaneous parasitic leiomyoma in a 30-year-old post-partum woman. A subserosal leiomyoma had been noted at the first trimester screening, and she had experienced persistent abdominal pain during her previous pregnancy. She was referred to hospital with severe abdominal pain at 7 months after delivery. We detected a homogenous solid tumor that resembled the subserosal leiomyoma but was completely detached from the uterus. On laparoscopy the vascularization of the tumor was supplied from the omentum, which was tightly adherent to the tumor. Histopathologically, the tumor was surrounded by a fibrous vascular capsule, and broadly hyalinized and partially calcified, consistent with a degenerated uterine leiomyoma. Detachment of a pedunculated subserosal leiomyoma from the uterus following adhesion to other pelvic structures throughout pregnancy may result in a parasitic leiomyoma, a rare subtype of uterine leiomyoma.
Keywords: gravid uterus; parasitic leiomyoma; pregnancy; subserosal leiomyoma.
© 2016 Japan Society of Obstetrics and Gynecology.