Case report of schwannoma of the rectum--clinical and pathological contribution.

The case of benign schwannoma of the rectum primarily misdiagnosed as myogenic (neurogenic?) sarcoma is presented. A large tumor of 8 cm in diameter of the anterior rectal wall was removed with wide margins and an artificial anus was constructed. During 12 years of follow-up neither local recurrence nor distant metastases were observed. The patient is still alive and free of the disease. For that reason a surgery specimen of the tumor was pathologically reanalyzed and it showed features of type Antoni A and B tissues. These findings, together with strong reactivity for S-100 protein, Vimentin and negative for Actin supported the diagnosis of benign schwannoma. Because the localization of the tumor in the rectum is extremely rare, clinical and pathological features are presented and discussed.