Perineal schwannoma

Schwannoma is a benign tumor arising from Schwann cells of the peripheral nerve sheath. Perineal schwannomas are exceptional, and rarely reported in the literature. We report a case of a perineal schwannoma, close to the anal sphincter, and provide a short summary of clinical, radiological and surgical features of this rare entity.

A 62 year-old male patient was admitted for a suspected perineal mass. At clinical examination, he had a soft mass, located on the right of the anus. Computed tomography showed a perineal mass, located on the right side of the anal sphincter that enhanced after injection of the contrast medium. Complete surgical excision of the tumor was performed. The most challenging part during the surgery was the dissection and preservation of the anal sphincter to avoid anal incontinence. Pathologic examination revealed a completely excised schwannoma.

Perineal schwannomas are very rare tumors that are usually asymptomatic, and which present as large masses. Complete excision is necessary to avoid recurrences. Surgical resection may be difficult depending of proximity to the anal sphincter. A cautious dissection in such cases is required in order to reduce the risk of incontinence.