title: Pathological characteristics of gastrointestinal stromal tumours with PDGFRA mutations.
abstract: OBJECTIVE
  The aim of this study was to identify the characteristics of PDGFRA-mutated gastrointestinal stromal tumours (GISTs) in comparison with KIT-mutated GISTs.
  
  
  METHODS
  A total of 151 GISTs were examined for KIT and PDGFRA mutations, and clinical and histopathological parameters were evaluated and analysed statistically according to mutation status.
  
  
  RESULTS
  KIT and PDGFRA mutations were detected in 123 (81.5%) and 15 cases (9.9%), respectively. Clinically, all PDGFRA-mutated GISTs were located in the stomach with no recurrences and tumour-related deaths were noted. Pathological parameters associated with PDGFRA mutations were epithelioid and mixed type, low to moderate cellularity, moderate to severe intratumoural lymphocytic infiltration, prominent myxoid change, frequent rhabdoid cells and multinucleated giant cells, increased cellular pleomorphism, low mitotic count, and lower risk assessment (p < 0.05). Compared with KIT-mutated GISTs, PDGFRA-mutated GISTs had unique histopathological patterns, intermingling of spindle and epithelioid cells, and/or a jigsaw puzzle-like arrangement of epithelioid cells.
  
  
  CONCLUSIONS
  PDGFRA-mutated GISTs have distinctive histological patterns that are differentiated from KIT-mutated GISTs. The algorithmic approach by a combination of several distinguishing histological and immunohistochemical features between KIT- and PDGFRA-mutated GISTs might be helpful in predicting the mutated gene of each GIST on pathological examination.
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seodaemun-Gu, Seoul, Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Kwon
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Kang
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Lee
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Hyung
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Noh
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
authors.forename: Hoguen
authors.initials: H
authors.lastname: Kim
mesh_terms: D000465:Algorithms; D002452:Cell Count; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D009154:Mutation; D009364:Neoplasm Recurrence, Local; D018807:Polymorphism, Single-Stranded Conformational; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics*; D056910:Republic of Korea / Q000453:epidemiology; D015996:Survival Rate; D046888:Tissue Array Analysis
chemical_list: D004273:DNA, Neoplasm; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha