Extra-Gastrointestinal stromal tumor of the pancreas with c-KIT gene mutation: Report of a case

ABSTRACT

Mesenchymal tumors of the pancreas are quite rare, accounting for less than 1% of all pancreatic tumors. Mesenchymal tumors in the gastrointestinal tract are mainly gastrointestinal stromal tumors (GISTs). GISTs are defined as KIT-positive mesenchymal spindle cells or epithelioid neoplasms originating from the interstitial cell of Cajal. GISTs occur mainly in the stomach, small intestine, colorectum and esophagus. However, extra-gastrointestinal stromal tumors in the bladder, gallbladder, omentum, and mesentery are rare. We report a case of GIST in the pancreas head. A 55-year-old female patient was referred to our hospital for a pancreas head mass detected by a CT scan checked for a fever with an unknown origin. She underwent Whipple's operation for the 5.5x4.4cm-sized mass located in the pancreas head. A microscopic examination revealed GIST showing positive c-KIT protein expression with <5/50 HPF mitosis. C-KIT gene analysis revealed a mutation in exon 9. To the best of our knowledge, this is the first case of extra-gastrointestinal stromal tumor of the pancreas demonstrated by histology, immunohistochemistry and genetic analysis in Korea.