title: Small bud of probable gastrointestinal stromal tumor within a laparoscopically-resected gastric schwannoma.
abstract: Submucosal tumors (SMTs) of the gastrointestinal (GI) tract can be potentially difficulty to diagnose pathologically. We report a case of a gastric SMT that was resected by laparoscopic partial gastrectomy. Although the initial histological and immunohistochemical examinations considered the tumor as a schwannoma, mRNA-based KIT genotyping indicated that the tumor included cells with KIT gene expression, and that a small number of cells carried a deletion mutation in exon 11. Additional histopathological investigations revealed small aggregates of enlarged spindle to epithelioid cells, which were positive for KIT, CD34 and DOG1, and negative for S-100, scattered among the S-100-positive schwannoma cells. We consider that the cells carrying the KIT gene mutation are microscopic buds of a gastrointestinal stroma tumor (GIST), and to the best of our knowledge, this is the first report of probable GIST tissues identified in a schwannoma. Our observations raised the significance of genotyping for diagnosis of GI tract SMTs.
authors.affiliation: Department of Gastrointestinal Surgery, Kanagawa Cancer Center Hospital, 1-1-2 Nakao, Asahi-ku, Yokohama, 241-0815, Japan. choharuhiko@kcch.jp
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Cho
authors.forename: Takafumi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Toru
authors.initials: T
authors.lastname: Aoyama
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hayashi
authors.forename: Takanobu
authors.initials: T
authors.lastname: Yamada
authors.forename: Takashi
authors.initials: T
authors.lastname: Ogata
authors.forename: Takaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuburaya
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sekiguchi
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sakuma
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kameda
authors.forename: Yohei
authors.initials: Y
authors.lastname: Miyagi
mesh_terms: D005770:Gastrointestinal Neoplasms / Q000473:pathology*; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology*; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*; D009442:Neurilemmoma / Q000473:pathology*; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism
chemical_list: D019009:Proto-Oncogene Proteins c-kit