Extra-gastrointestinal stromal tumor of the pelvic cavity: case report

Med Mol Morphol. 2012 Jun;45(3):173-7. doi: 10.1007/s00795-011-0568-x. Epub 2012 Sep 22.


Extra-gastrointestinal stromal tumors (E-GISTs) not associated with the alimentary tract in the pelvic cavity are extremely rare. We treated a 49-year-old Japanese man with such an E-GIST in the pelvic cavity who underwent an intrapelvic tumorectomy with a total prostatectomy and partial rectum resection. Gross examination of the specimen revealed an 8.1 × 5 × 4 cm white-grayish mass. Histological findings showed uniform spindle cells with scant atypia that formed interlacing bundles or whorl patterns. These neoplastic cells did not invade adjacent organs, including the gut. Immunohistochemical findings revealed that the neoplastic cells were positive for c-kit, CD34, and vimentin. Molecular analysis showed a c-kit mutation at exon 9 with duplication of Ala and Tyr. Our diagnosis was E-GIST, which belongs to the intermediate group of GIST. Following the operation, we administered imatinib mesylate for 6 months. After stopping for 5 months, it was administered again for local recurrence. We are planning our future strategy for this case including surgical resection as necessary.

Publication types

  • Case Reports

MeSH terms

  • Antigens, CD34 / genetics
  • Antigens, CD34 / metabolism
  • Antineoplastic Agents / therapeutic use
  • Benzamides
  • Exons / genetics
  • Gastrointestinal Stromal Tumors / diagnosis
  • Gastrointestinal Stromal Tumors / drug therapy
  • Gastrointestinal Stromal Tumors / pathology
  • Gastrointestinal Stromal Tumors / surgery
  • Humans
  • Imatinib Mesylate
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Mutation
  • Pelvis* / pathology
  • Pelvis* / surgery
  • Piperazines / therapeutic use
  • Proto-Oncogene Proteins c-kit / genetics
  • Proto-Oncogene Proteins c-kit / metabolism
  • Pyrimidines / therapeutic use
  • Vimentin / genetics
  • Vimentin / metabolism


  • Antigens, CD34
  • Antineoplastic Agents
  • Benzamides
  • Piperazines
  • Pyrimidines
  • Vimentin
  • Imatinib Mesylate
  • Proto-Oncogene Proteins c-kit