title: Electron microscopic and immunohistochemical studies of gastrointestinal stromal tumors.
abstract: Sixteen gastrointestinal stromal tumors (GISTs) were studied by immunohistochemical analysis and an ultrastructural procedure. The tumor locations were as follows: esophagus (2), stomach (7), small intestine (3), and large intestine (4). Four of the lesions were classified as malignant, 2 as borderline, and 10 as benign. On the basis of the immunohistochemical analysis, the tumors were classified as follows: 1 as myogenic type, 2 as Schwann cell type, 8 as Cajal cell type (including 2 gastrointestinal autonomic nerve tumors, GANTs), and 5 as mixed-cell type. In each subtype the phenotype was compared to the ultrastructural findings. Myogenic and Schwann cell type revealed ultrastructurally smooth muscle differentiation and schwannian tumor. All 8 tumors of the Cajal cell type revealed interdigitating cytoplasmic processes with occasional clusters of filopodia. Two tumors were subdivided as GANT. Five tumors of mixed-cell type were composed of a mixture of cells with variable myogenic features or variable neural differentiation. We confirmed in this study that immunohistochemical analysis reflected electron microscopic findings.
authors.affiliation: Department of Pathology, Obihiro Kosei General Hospital, Minami 8-chome, Nishi 6-jo, Obihiro 080-0016, Japan.
authors.forename: J.
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Norimasa
authors.initials: N
authors.lastname: Sawada
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Tobioka
authors.forename: Reiko
authors.initials: R
authors.lastname: Takakuwa
authors.forename: Tomoko
authors.initials: T
authors.lastname: Goto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sakuma
authors.forename: Tatsuru
authors.initials: T
authors.lastname: Ikeda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Satoh
authors.forename: Michio
authors.initials: M
authors.lastname: Mori