title: Bilateral gluteal metastases from a misdiagnosed intrapelvic gastrointestinal stromal tumor.
abstract: BACKGROUND
  The location of gastrointestinal stromal tumors (GIST) outside of the gastrointestinal system is a rare event.
  
  
  METHODS
  A 56-year old woman presented with a GIST of the pelvis was misdiagnosed and treated as a uterine leiomyosarcoma. The diagnosis was made after the CD117 (KIT) positivity in the biopsy of the excised bowel mass four years from the first presentation. During this period she presented a bilateral muscle and subcutaneous metastasis in the gluteal area.
  
  
  CONCLUSIONS
  The correct diagnosis of the extra-gastrointestinal stromal tumor is a challenge even for experienced pathologists. CD117 (KIT) positivity is the most important immunohistochemical feature in the histological diagnosis. To our knowledge a metastatic EGIST (extra-gastrointestinal stromal tumor) to the skeletal muscle bilaterally has not been described previously in the English medical literature.
authors.affiliation: Department of Orthopaedic and Traumatology, University Hospital of Heraklion, Crete, Greece. paskudr@hotmail.com
authors.forename: Dritan
authors.initials: D
authors.lastname: Pasku
authors.forename: Apostolos
authors.initials: A
authors.lastname: Karantanas
authors.forename: Elpida
authors.initials: E
authors.lastname: Giannikaki
authors.forename: Maria
authors.initials: M
authors.lastname: Tzardi
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Velivassakis
authors.forename: Pavlos
authors.initials: P
authors.lastname: Katonis
mesh_terms: D002081:Buttocks; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D010386:Pelvic Neoplasms / Q000175:diagnosis / Q000473:pathology*; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D012983:Soft Tissue Neoplasms / Q000556:secondary*; D050151:Subcutaneous Fat / Q000473:pathology
chemical_list: D019009:Proto-Oncogene Proteins c-kit