OBJECTIVE

Present the case of a patient with a pelvic mass which was reported as myoma and turned out to be a schwannoma.

CLINICAL CASE

We report a case of a 53 year old female that presented with abdominal and low back pain, also distention, constipation and dyspareunia for 3 months. Transvaginal ultrasound suggested leiomyoma. Laparoscopic hysterectomy was planned. On laparoscopy, a retroperitoneal 9 cm mass was seen over de sacrum. The procedure was stopped for further studies. Magnetic resonance images detected a large presacral solid, tumor of 8 cm. The patient was scheduled for laparoscopy with oncology group and the mass was resected. No complications were experienced intra or postoperatively. The final histological diagnosis was a cellular schwannoma, that was S-100- positive, and smooth muscle actin-negative. A follow up consultation 6 months later showed a significant improvement of the lower abdominal pain.

CONCLUSIONS

Schwannomas rarely present as pelvic masses. We report a woman with a pelvic mass initially diagnosed as a uterine fibroid but subsequently proven to be a retroperitoneal schwannoma. This rare entity is usually asymptomatic or has nonspecific symptoms leading to misdiagnosis. Preoperative diagnosis of a schwannoma is not easy for a lack of distinguishing features on imaging studies. The prognosis of schwannoma is excellent, and the excision is usually curative.