title: Gastrointestinal stromal tumor of the anal canal: an unusual presentation.
abstract: BACKGROUND
  Gastrointestinal stromal tumors (GIST) of the stomach are the most frequent followed by those of the intestinal tract, while colon and rectum represent rare sites. GIST of the anal canal are extremely rare. They have been studied along with GIST of the rectum, as a single entity, and along with them they represent 5% of GIST. GIST arising from the anal canal account for only 2%-8% of the anorectal GIST. Thus anal GIST must be considered an exceptional case.
  
  
  METHODS
  A 78-year-old man was referred to our Institution for an anal mass, in absence of any symptom. The patient was treated by local excision. An histological diagnosis of a low grade GIST was made. No further treatment was necessary. No local recurrence of distant metastases were found at follow-up.
  
  
  CONCLUSIONS
  At the moment, only ten cases of c-kit positive anal GIST are reported in the literature. These few data are not sufficient to establish a widely accepted approach for this neoplasia. We recommend to perform an initial local excision, to define the risk of aggressive behavior and the resection margins and proceed to a more aggressive treatment, if the GIST belongs to high or very high risk group. The role of adjuvant therapy is still uncertain. Although inhibitors of tyrosine-kinase receptor needs further studies before their routine use, their role in case of distant or local recurrence has been accepted. Patients' close follow up is mandatory to disclose as soon as possible local recurrences or metastases.
authors.affiliation: Department of Surgery, University of Rome La Sapienza, 2nd School of Medicine, Sant'Andrea Hospital, Rome, Italy. giuseppe.nigri@uniroma1.it
authors.forename: Giuseppe R
authors.initials: GR
authors.lastname: Nigri
authors.forename: Mario
authors.initials: M
authors.lastname: Dente
authors.forename: Stefano
authors.initials: S
authors.lastname: Valabrega
authors.forename: Paolo
authors.initials: P
authors.lastname: Aurello
authors.forename: Francesco
authors.initials: F
authors.lastname: D'Angelo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Montrone
authors.forename: Giorgio
authors.initials: G
authors.lastname: Ercolani
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ramacciato
mesh_terms: D000368:Aged; D001003:Anal Canal / Q000473:pathology*; D001005:Anus Neoplasms / Q000473:pathology* / Q000601:surgery*; D001707:Biopsy, Needle; D019160:Endosonography; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009367:Neoplasm Staging; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome