A c-kit-negative gastrointestinal stromal tumor with a platelet-derived growth factor receptor alpha mutation.
Gastrointestinal stromal tumors (GISTs) are well-recognized mesenchymal neoplasms of the intestinal tract. A diagnosis of GIST is not always possible using IHC techniques for detection of c-kit. The authors describe a 64-year-old man who presented with an upper abdominal quadrant mass. Histology showed a predominantly epithelioid neoplasm with focal "spindle cell" areas. IHC studies were positive for muscle markers and negative for c-kit. The morphologic and immunophenotypic appearance could be compatible with either a smooth muscle tumor or a GIST. Because of the differences in treatment protocols and prognosis between these two entities, molecular studies to detect c-kit or platelet-derived growth factor receptor (PDGFR) activating mutations were performed. No mutations were found in the c-kit gene, but a mutation was detected in the PDGFR gene. This additional molecular study allowed the authors to formulate the precise diagnosis of a c-kit-negative GIST with strong smooth muscle marker expression.
Isaac
Jorge C
JC
University of Utah, Health Sciences Center, Salt Lake City, Utah. jorge.isaac@path.utah.edu
Willmore
Carlynn
C
Holden
Joseph A
JA
Layfield
Lester J
LJ
D000368:Aged; D001483:Base Sequence; D004252:DNA Mutational Analysis; D003893:Desmin / Q000378:metabolism; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis* / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics*
D003893:Desmin; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha