title: Metachronic malignant transformation of small bowel and rectal endometriosis in the same patient.
abstract: BACKGROUND
  Malignant transformation of intestinal endometriosis is a rare event with an unknown rate of incidence. Metachronous progression of endometriosis to adenocarcinoma from two distant intestinal foci happening in the same patient has not been previously reported.
  
  
  METHODS
  We describe a case of metachronic transformation of ileal and rectal endometriosis into an adenocarcinoma occurring in a 45-year-old female without macroscopic pelvic involvement of her endometriosis. First, a right colectomy was performed due to intestinal obstruction by an ileal mass. Pathological examination revealed an ileal endometrioid adenocarcinoma and contiguous microscopic endometriotic foci. Twenty months later, a rectal mass was discovered. An endoscopic biopsy revealed an adenocarcinoma. En bloc anterior rectum resection, hysterectomy and bilateral salpingectomy were performed. A second endometrioid adenocarcinoma arising from a focus of endometriosis within the wall of the rectum was diagnosed.
  
  
  CONCLUSIONS
  Intestinal endometriosis should be considered a premalignant condition in premenopausal women.
authors.affiliation: Department of General Surgery, University Hospital Gran Canaria Dr. Negrin, Las Palmas GC, Spain. jmarchena@dcmq.ulpgc.es
authors.forename: Joaquin
authors.initials: J
authors.lastname: Marchena-Gomez
authors.forename: Alicia
authors.initials: A
authors.lastname: Conde-Martel
authors.forename: Marion
authors.initials: M
authors.lastname: Hemmersbach-Miller
authors.forename: Ana
authors.initials: A
authors.lastname: Alonso-Fernandez