title: A gastrointestinal stromal tumor of the stomach morphologically resembling a neurofibroma: demonstration of a novel platelet-derived growth factor receptor alpha exon 18 mutation.
abstract: Gastrointestinal stromal tumors are increasingly being recognized because of their characteristic expression of KIT (CD 117). Most KIT-positive gastrointestinal stromal tumors have activating mutations in the c-kit gene. A subgroup of gastrointestinal stromal tumors are negative for KIT expression, and in these tumors, activating mutations in platelet-derived growth factor receptor alpha are common. Most platelet-derived growth factor receptor alpha mutation-positive gastrointestinal stromal tumors show an epithelioid histology and are located in the stomach. Herein, we describe an unusual gastric stromal tumor. The tumor was negative for KIT expression and the morphology did not show an epithelioid pattern but rather was composed of bland spindle cells reminiscent of a neurofibroma. Molecular analysis revealed a somatic mutation in platelet-derived growth factor receptor alpha exon 18 (D842F). Aside from demonstrating a new platelet-derived growth factor receptor alpha mutation, this case illustrates the usefulness of molecular testing as a diagnostic tool and clearly indicates the wide range of morphology that can be observed in gastrointestinal stromal tumors.
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA. ting.liu@path.utah.edu
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.forename: Carlynn
authors.initials: C
authors.lastname: Willmore-Payne
authors.forename: Lester J
authors.initials: LJ
authors.lastname: Layfield
authors.forename: Robert E
authors.initials: RE
authors.lastname: Glasgow
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Holden
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D003937:Diagnosis, Differential; D005091:Exons; D005260:Female; D005743:Gastrectomy; D046152:Gastrointestinal Stromal Tumors / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009154:Mutation; D009455:Neurofibroma; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D016133:Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D010982:Platelet-Derived Growth Factor; C075278:platelet-derived growth factor A