title: MDCT features of succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumours.
abstract: OBJECTIVE
  To describe the multidetector CT (MDCT) features and metastatic pattern of succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumours (GISTs).
  
  
  METHODS
  In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, we retrospectively identified 34 patients (20 females; mean age, 34 years; range, 12-59 years) with histopathology-confirmed SDH-deficient GIST, who were seen at our institution from 1999 through 2012. MDCT of primary tumour in 8 patients and follow-up imaging in all 34 patients over median follow-up of 106 months [interquartile range (IQR), 52-175 months] were reviewed by two radiologists in consensus. Clinical information was extracted from electronic medical records.
  
  
  RESULTS
  Primary tumour in all 34 patients was located in the stomach. Mean tumour size (n = 8) was 9.6 cm (range, 8-14 cm). Primary tumours were lobulated, variable in growth pattern, hypo- (1/8) to isodense (7/8) and similar in enhancement to the skeletal muscle. Two were multifocal, four of eight had necrosis and one of eight had haemorrhage. Tumour rupture with haemoperitoneum and tumour-bowel fistula was noted in one patient each. During follow-up, 12/34 patients developed tumour in surgical bed, and 28/34 patients developed metastases. Most common sites of metastases were the liver (24/34), peritoneum (20/34) and lymph nodes (18/34). Carney triad and Carney-Stratakis syndrome were noted in 5/34 and 1/34 patients, respectively. At the time of writing, six patients had deceased at a median interval of 109 months (IQR, 54-126 months).
  
  
  CONCLUSIONS
  SDH-deficient GISTs occur in young patients, commonly arise in stomach, can be multifocal and may be associated with Carney triad or Carney-Stratakis syndrome. They frequently metastasize to lymph nodes in addition to the liver and peritoneum and are associated with indolent course despite metastatic spread.
  
  
  CONCLUSIONS
  The presence of features unusual for conventional GIST on imaging should alert the radiologist for the possibility of SDH-deficient GIST, especially, because SDH-deficient GISTs are resistant to imatinib. Young age at diagnosis, prolonged survival, association with Carney triad and Carney-Stratakis syndrome and occurrence of concurrent renal cell carcinoma and thyroid malignancies necessitates long-term follow-up of patients with SDH-deficient GISTs.
authors.affiliation: 1 Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Tirumani
authors.forename: H
authors.initials: H
authors.lastname: Tirumani
authors.forename: J P
authors.initials: JP
authors.lastname: Jagannathan
authors.forename: A B
authors.initials: AB
authors.lastname: Shinagare
authors.forename: J L
authors.initials: JL
authors.lastname: Hornick
authors.forename: S
authors.initials: S
authors.lastname: George
authors.forename: A J
authors.initials: AJ
authors.lastname: Wagner
authors.forename: N H
authors.initials: NH
authors.lastname: Ramaiya
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging* / Q000201:enzymology; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013385:Succinate Dehydrogenase / Q000172:deficiency*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D013385:Succinate Dehydrogenase