We report a case of a patient admitted to our hospital for acute pelvic pain. Ultrasounds and abdominal CT scan found a voluminous mass situated in the upper urinary bladder and contiguous to the uterus and to the ovaries. Magnetic resonance imaging identified a pedicle connecting the uterus to the mass which had an aspect of a necrobiotic leiomyoma. Laparoscopic surgery confirmed the diagnosis of acute torsion of a subserous uterine leiomyoma.