title: Local excision of rectal schwannoma using transanal endoscopic microsurgery: A case report.
abstract: BACKGROUND
  Schwannoma is a neoplasm originating from the neural crest cells (schwann cells) that form nerve sheaths. These tumors are thought to be benign with little risk of malignant transformation. They rarely affect the gastrointestinal tract, and primary rectal involvement is extremely rare. Until 2013, only 11 cases of anorectal schwannoma have been reported. Optimal surgical treatment of rectal schwannoma has not been established.
  
  
  METHODS
  We herein describe a 70-year-old woman with a submucosal tumor arising from the posterior wall of the rectum with features mimicking a gastrointestinal stromal tumor. After discussing the operative procedures and obtaining written informed consent, we attempted local excision of the tumor using a transanal endoscopic microsurgery (TEM). The tumor was proved to be S-100 positive schwannoma on immuhistochemical studies. Her postoperative course was uneventful, and there is no evidence of tumor recurrence as of 6 months after surgical excision.
  
  
  CONCLUSIONS
  An extremely rare rectal schwannoma was successfully treated using a TEM without compromising anorectal function.
  
  
  CONCLUSIONS
  TEM is a feasible approach for local excision of rectal tumors with low risk of malignancy.
authors.affiliation: Department of Surgery, Daisan Hospital, The Jikei University School of Medicine, Japan. Electronic address: toshiaki1129jp@yahoo.co.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Surgery, Daisan Hospital, The Jikei University School of Medicine, Japan.
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Suwa
authors.affiliation: Onaka Clinic.
authors.forename: Takenori
authors.initials: T
authors.lastname: Hada
authors.affiliation: Department of Surgery, Daisan Hospital, The Jikei University School of Medicine, Japan.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Fujita
authors.affiliation: Department of Surgery, The Jikei University School of Medicine, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yanaga
keywords: Rectal shwannoma; Transanal endoscopic microsurgery (TEM)