title: "Wild type" GIST: Clinicopathological features and clinical practice.
abstract: Gastrointestinal stromal tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract. Mutation of KIT and PDGFRA genes is implicated in the tumorigenesis. Approximately 10% of GISTs do not harbor mutation of these genes, and they are designated as "wild type" GIST. They are classified into succinate dehydrogenase (SDH)-deficient and non-SDH-deficient groups. SDH-deficient group includes Carney triad and Carney Stratakis syndrome. The patients are young women. Tumors occur in the antrum of the stomach, and tumor cells are epithelioid. Lymph node metastasis is frequent. The non-SDH-deficient group includes neurofibromatosis (NF) type 1 and GISTs with mutations of BRAF, KRAS, and PIK3CA and with the ETV6-NTRK3 fusion gene. GIST in NF occurs in the small intestine, and tumor cells are spindle shaped. GIST with BRAF mutation arises in the small intestine. Attention to the age, gender, family history and other neoplasms may raise the prediction of syndromic disease. Location of the tumor, morphology, and pleomorphism of the tumor cells are further informative. Lymphovascular invasion should be carefully evaluated. The determination of KIT expression is essential for the diagnosis. When wild type GIST is suspected, intensive genetic analysis is required. Further, a careful and long-time observation is recommended.
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Wada
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Arai
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Kure
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Wei-Xia
authors.initials: WX
authors.lastname: Peng
authors.affiliation: Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Zenya
authors.initials: Z
authors.lastname: Naito
mesh_terms: D000328:Adult; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000145:classification* / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: BRAF; Carney Stratakis syndrome; Carney triad; ETV6-NTRK3; Gastrointestinal stromal tumor; KRAS; Neurofibromatosis; PIK3CA; Succinate dehydrogenase