title: [Clinicopathologic features of succinate dehydrogenase-deficient gastrointestinal stromal tumor].
abstract: OBJECTIVE
  To investigate clinicopathologic features of succinate dehydrogenase-deficient gastrointestinal stromal tumors (SDH-deficient GIST).
  
  
  METHODS
  Immunohistochemical EnVision technique was used to assess the expression of succinate dehydrogenase subunit B (SDHB) in 192 cases of GIST. Cases of SDH-deficient GIST were further evaluated for the presence of CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations with clinical followed-up data.
  
  
  RESULTS
  Seven of the 192 cases showed SDHB-deficiency (3.6%, 7/192). The patients ranged in age from 35 to 84 years (median=56 years; mean=60 years). Four were male and three were female. Six tumors involved stomach and one involved mesentery. Histopathologic features of SDHB-deficient GIST included four cases of mixed-cell type and three of epithelioid cell type. The tumors commonly involved muscularis propria of the stomach as multiple nodules, creating a plexiform pattern. The tumors had high cellularity with cytoplasmic vacuolization. Five cases developed lymph node metastases including one also metastasizing to liver and pancreas. Two cases showed no evidence of metastasis. None of the 7 cases of the SDHB-deficient GIST had CKIT exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations. Three of the seven SDHB-deficient GIST cases had followed-up data: two did not recur and one died after 24 months of surgery of unknown cause.
  
  
  CONCLUSIONS
  SDHB-deficient GIST has characteristic clinicopathologic features with wide-type CKIT gene and a favorable prognosis.
authors.affiliation: Department of Pathology, Guizhou Medical University and the Affiliated Hospital of Guizhou Medical University, Guiyang 550004, China.
authors.forename: Yuanhua
authors.initials: Y
authors.lastname: Cheng
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Hefen
authors.initials: H
authors.lastname: Zhu
authors.forename: Lixin
authors.initials: L
authors.lastname: Guo
authors.forename: Yuandong
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005091:Exons; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011379:Prognosis; D013385:Succinate Dehydrogenase / Q000235:genetics*
chemical_list: C491545:SDHD protein, human; D013385:Succinate Dehydrogenase