Abstract
Schwannomas occur in peripheral nerves mainly in the upper and lower limbs. We treated a patient with a schwannoma in a very rare location, the rectus abdominis muscle. A 53-year-old woman noted an abdominal wall mass in the left lower quadrant and was referred to our hospital for further evaluation. Abdominal ultrasonography showed a 4-cm hypoechoic mass adjacent to the rectus abdominis muscle. Enhanced CT scan of the abdomen demonstrated gradual enhancement of the tumor. Abdominal enhanced MRI scan showed heterogeneous enhancement in T1-weighted images and heterogeneously high intensity in T2-weighted images of the tumor. A desmoid tumor of the abdominal wall was first suspected and excision of the tumor was planned. The operation proceeded without difficulty with resection of the mass including a partial resection of the rectus abdominis muscle. The tumor was diagnosed as a schwannoma by histopathological findings without evidence of malignancy. Schwannomas arising from the rectus abdominis muscle are very rare and so far six cases have been reported, but we should consider this disease when evaluating a mass of the rectus abdominis muscle.
