Resection of a pelvic schwannoma with partial removal of the sacral nerve root.

Because the symptoms do not appear in most cases until the tumor has grown quite large, schwannomas are often detected incidentally during work-up for some other condition. Benign schwannomas generally do not invade adjacent structures but making the diagnosis preoperatively can be difficult when the tumor is large. We report the case of a benign schwannoma which was diagnosed preoperatively by needle core biopsy under computed tomography guidance. The tumor was removed completely by partially resecting the S1 nerve root, which was subsequently reanastomosed. The postoperative course was uneventful with the exception of minimal left leg pain due to neurologic deficit.