title: Rare extraskeletal Ewing's sarcoma mimicking as adenocarcinoma of the sigmoid.
abstract: BACKGROUND
  Extraskeletal Ewing's sarcoma (EES) is a rare finding in comparison with Ewing's sarcoma of bone and usually manifests in young patients. However, even in older patients, one must consider the diagnosis.
  
  
  METHODS
  In this case, we describe a 52-year-old woman diagnosed with EES, mimicking as adenocarcinoma of the sigmoid.
  
  
  RESULTS
  The tumor was not visualized by a multi-slice spiral computed tomography of the abdomen and pelvis with intravenous contrast, and eventually the diagnosis was made by positive immunohistochemical staining for CD99 and by molecular testing for EWSR1 translocation.
  
  
  CONCLUSIONS
  This combination of the patient's age and the localization of the tumor mimicking an adenocarcinoma of the sigmoid has never been described before.
authors.affiliation: a Department of General Surgery, Antwerp University Hospital , Edegem , Belgium.
authors.forename: Michelle
authors.initials: M
authors.lastname: Mertens
authors.affiliation: b Department of General Surgery , AZ Monica , Deurne , Belgium.
authors.forename: Filip W N
authors.initials: FW
authors.lastname: Haenen
authors.affiliation: c Department of Pathology , Antwerp University Hospital , Edegem , Belgium.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Siozopoulou
authors.affiliation: b Department of General Surgery , AZ Monica , Deurne , Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Van Cleemput
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000628:therapy; D012811:Sigmoid Neoplasms / Q000175:diagnosis* / Q000628:therapy
keywords: Ewing’s sarcoma; Extraskeletal Ewing’s sarcoma; abdominal surgery; general surgery