Resumen

OBJETIVO: Exponer el caso de una paciente con una masa pélvica que se reportó como mioma y resultó ser un schwannoma. 

CASO CLÍNICO: Paciente de 53 años que consultó por dolor abdominal, lumbalgia, distensión, estreñimiento y dispareunia durante tres meses. La ecografía transvaginal sugirió un leiomioma. En la histerectomía laparoscópica se observó una masa retroperitoneal de 9 cm sobre el sacro. La resonancia magnética reportó un tumor sólido, presacro, de 8 cm. El diagnóstico histológico final fue: schwannoma celular S-100 positivo y actina de la musculatura lisa negativa. El seguimiento a los seis meses posteriores demostró disminución significativa del dolor abdominal inferior. 

CONCLUSIONES: Los schwannomas se manifiestan, excepcionalmente, como masas pélvicas, como fue el caso aquí comunicado que se diagnosticó como fibroma uterino, pero que posteriormente se demostró era un schwannoma retroperitoneal. Este tumor pocas veces genera síntomas y cuando los hay suelen ser inespecíficos, por eso frecuentemente el diagnóstico es erróneo. Por la falta de características distintivas en los estudios de imagen el diagnóstico preoperatorio de un schwannoma no es fácil; su pronóstico es excelente y la escisión suele ser curativa.

PALABRAS CLAVES: Schwannoma retroperitoneal; leiomioma; schwannoma celular; dolor abdominal inferior.

Abstract

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.

KEYWORDS: Retroperitoneal schwannoma; Leiomyoma; Cellular schwannoma; Lower abdominal pain.