title: Keratin-positive gastrointestinal stromal tumor of the stomach mimicking gastric carcinoma: diagnosis confirmed by c-kit mutation analysis.
abstract: In routine practice, gastrointestinal stromal tumor (GIST) can usually be identified with relative ease on the basis of a rather simple immunohistochemical panel besides its characteristic morphology. Still, serious differential diagnostic problems may arise because of the heterogeneity of these tumors in both morphologic appearance and clinical behavior. In our case, we present a metastatic, ulcerative, hemorrhagic GIST with epithelioid appearance, which displayed diffuse pan cytokeratin (AE1/AE3) positivity beside CD117 expression. As carcinomas may also be CD117-positive, definitive diagnosis was confirmed by the detection of a hexanucleotide deletion in the exon 11 of c-kit. This case demonstrates that although gastric carcinoma more commonly ulcerates or causes hemorrhage than GIST, keratin-positive GIST should also be considered from a differential diagnostic point of view. In these cases, c-kit mutation analysis may be necessary.
authors.affiliation: Department of Pathology, Bajcsy Zsilinszky Hospital, Budapest, Hungary.
authors.forename: Norbert
authors.initials: N
authors.lastname: Lippai
authors.forename: Tibor
authors.initials: T
authors.lastname: Füle
authors.forename: Tamás
authors.initials: T
authors.lastname: Németh
authors.forename: György
authors.initials: G
authors.lastname: Benedek
authors.forename: Imre
authors.initials: I
authors.lastname: Mályi
authors.forename: Eva
authors.initials: E
authors.lastname: Pádi
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Sápi
mesh_terms: D002277:Carcinoma / Q000175:diagnosis; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D005091:Exons; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology*; D017353:Gene Deletion; D006801:Humans; D007633:Keratins / Q000032:analysis*; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis / Q000235:genetics*; D017384:Sequence Deletion; D013274:Stomach Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D007633:Keratins; D019009:Proto-Oncogene Proteins c-kit