title: Complete pathological response to Imatinib mesylate in an extraintestinal gastrointestinal stromal tumor.
abstract: BACKGROUND
  Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumors of the digestive tract. Extraintestinal locations (EGIST) have been described showing similar pattern of immunohistochemical markers than GIST. Inhibitors of tyrosine kinases such as Imatinib or Sunitinib are the mainstay treatment in the management of advanced or metastatic GIST. Complete pathological response to these agents is an extremely rare event, especially in the case of EGIST due to its more aggressive behavior reported.
  
  
  METHODS
  Here we describe the case of a 61 years old woman, with an advanced GIST, who was operated after 10 months of Imatinib mesylate. The biopsy demonstrated the extra intestinal location of the tumor and a complete pathological response was confirmed.
  
  
  CONCLUSIONS
  Complete pathological response to Imatinib is a rare event. To our knowledge, this is the first report of complete response in an EGIST. New clinical, radiological and metabolic criteria of tumoral response to neoadjuvant treatment are revised.
  
  
  CONCLUSIONS
  EGIST complete pathological response to Imatinib can be achieved. However, recommendation of systematic neoadjuvant therapy with Imatinib remains investigational and more studies are warranted in the future.
authors.affiliation: Digestive Surgery Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Quezada
authors.affiliation: Hematology-Oncology Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Acevedo
authors.affiliation: Digestive Surgery Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Andrés
authors.initials: A
authors.lastname: Marambio
authors.affiliation: Digestive Surgery Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: León
authors.affiliation: Hematology-Oncology Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Hector
authors.initials: H
authors.lastname: Galindo
authors.affiliation: Pathology Department, School of Medicine. Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Roa
authors.affiliation: Digestive Surgery Department, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 350, Patio Interior, Santiago 8320000, Chile. Electronic address: njarufe@med.puc.cl.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Jarufe
keywords: Complete pathological response; EGIST; GIST; Imatinib