RESUMEN
BACKGROUND: The natural history of uterine leiomyomas during pregnancy has been reported. CASE: A 39-year-old primigravida presented with vaginal spotting in the 10th week of pregnancy. Ultrasonic evaluation revealed a large intramural leiomyoma. Unsuccessful tocolysis at 25 weeks' gestation resulted in a cesarean section for breech presentation. At hysterotomy a 10-cm intramural leiomyoma was found in the right fundus and was left in situ. Six months later, at open laparotomy for myomectomy, the 10-cm leiomyoma was pedunculated, on a 4-cm stalk. CONCLUSION: Large intramural leiomyomas found at cesarean section may become pedunculated postpartally, thus making myomectomy easier and safer at a postpartum intervention than at the time of cesarean section. Also, prior knowledge of the possibility of myoma transformation from intramural to pedunculated postpartally may help in planning a later myomectomy. Myomectomy prior to pregnancy should be considered when it has caused a prior pregnancy complication.