title: Sphincter-saving resection by cluneal arched skin incision for a gastrointestinal stromal tumor (GIST) of the lower rectum: a case report.
abstract: BACKGROUND
  Planning the surgical strategy for a gastrointestinal stromal tumor (GIST) at the posterior wall of the lower rectum is difficult, as the procedures for the lower rectum are hampered by poor visualization and may cause anal dysfunction or discomfort. We report a novel procedure to resect a submucosal tumor of the rectum.
  
  
  METHODS
  A 75-year-old woman presented with metrorrhagia. Endovaginal ultrasonography showed a low echoic tumor. Computed tomography showed an enhanced tumor, measuring 5.3 × 4.2 cm, behind the rectum. Magnetic resonance imaging revealed a submucosal tumor of the rectum, measuring 5.3 cm at its greatest dimension. Colonoscopy showed that the distal tumor margin was 1 cm above the dentate line. Core needle biopsy of the tumor revealed the rectal GIST. After receiving neoadjuvant imatinib treatment, the tumor size decreased to 3.5 cm. During the operation, we approached the rectum and resected the posterior rectal wall, including the 3.5 × 3.5 cm tumor with a safety margin, making an arched incision at the buttocks to form a skin flap with the patient in a jackknife position. The histopathological diagnosis was GIST of the rectum. Her anorectal sphincter function was well preserved. No recurrence was seen during the 2-year follow-up.
  
  
  CONCLUSIONS
  This novel approach improves the operative field visibility in resecting a tumor with a safety margin and preserves a patient's anorectal sphincter function.
authors.affiliation: Department of Surgery, Chugoku Rosai Hospital, 1-5-1, Tagaya, Hiro, Kure City, Hiroshima, 737-0193, Japan. thiroes@gmail.com.
authors.forename: Hirofumi
authors.identifier: http://orcid.org/0000-0003-0159-4966
authors.initials: H
authors.lastname: Tazawa
authors.affiliation: Department of Surgery, Chugoku Rosai Hospital, 1-5-1, Tagaya, Hiro, Kure City, Hiroshima, 737-0193, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Hirata
authors.affiliation: Department of Internal Medicine, Chugoku Rosai Hospital, 1-5-1, Tagaya, Hiro, Kure City, Hiroshima, 737-0193, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kuga
authors.affiliation: Department of Diagnostic Pathology, Chugoku Rosai Hospital, 1-5-1, Tagaya, Hiro, Kure City, Hiroshima, 737-0193, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nishida
authors.affiliation: Department of Surgery, Chugoku Rosai Hospital, 1-5-1, Tagaya, Hiro, Kure City, Hiroshima, 737-0193, Japan.|Department of Gastroenterological and Transplant Surgery, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Sakimoto
keywords: Cluneal arched skin incision; Rectal GIST; Sphincter-saving operation