title: Gastrointestinal mesenchymal tumors - immunophenotypic classification and survival analysis.
abstract: The current definition of gastrointestinal tumors (GIST) as CD117-positive mesenchymal tumors of uncertain malignant potential fails to include a number of cases with similar histology. In an attempt to improve the classification of these neoplasms, we conducted an immunohistochemical analysis of 244 mesenchymal tumors with histological features of GIST. According to their immunophenotype, the tumors were classified as GISTs, which are characterized by CD117 (c-kit) expression; gastrointestinal CD117-negative CD34 positive stromal tumors (GINST); alpha-smooth muscle actin and/or desmin positive gastrointestinal leiomyogenic tumors (GILT); S-100 and glial fibrillary acidic protein positive gastrointestinal glial/schwannian tumors (GIGT); gastrointestinal neuronal/glial tumors (GINT), which are positive for S-100/glial fibrillary acidic protein plus neuronal/glial markers; and gastrointestinal fibrous tumors (GIFT), which are only vimentin positive. The most common type of tumors were GIST, followed in order of frequency by GINST, GILT, GIGT, GIFT, and GINT. GISTs did not show any preferential location, whereas GINSTs occurred almost exclusively in the stomach and duodenum, and GILTs preferentially in the large intestine. Over a median follow-up period of 71 months, malignant behavior, i.e., metastatic spread, was observed in all tumor types except GINTs. Malignancy was associated with distal gut location, high mitotic activity, large tumor size, and nuclear pleomorphism, though none of these criteria alone discriminated between benign and malignant. Kaplan-Meier analysis of disease-specific survival showed significant differences in the long-term outcome of the newly defined subgroups. We conclude that, despite strong morphological similarities, gastrointestinal mesenchymal tumors are heterogeneous in their immunophenotype and biology.
authors.affiliation: Department of Pathology, University of Kiel, Michaelisstr. 11, 24105 Kiel, Germany. prudolph@path.uni-kiel.de
authors.forename: Pierre
authors.initials: P
authors.lastname: Rudolph
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Chiaravalli
authors.forename: Ursula
authors.initials: U
authors.lastname: Pauser
authors.forename: Ilske
authors.initials: I
authors.lastname: Oschlies
authors.forename: Marija
authors.initials: M
authors.lastname: Hillemanns
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Gobbo
authors.forename: Miriam
authors.initials: M
authors.lastname: Marichal
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Eusebi
authors.forename: Heinz
authors.initials: H
authors.lastname: Höfler
authors.forename: Carlo
authors.initials: C
authors.lastname: Capella
authors.forename: Günter
authors.initials: G
authors.lastname: Klöppel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000032:analysis; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000145:classification* / Q000401:mortality / Q000473:pathology; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D016019:Survival Analysis
chemical_list: D018952:Antigens, CD34; D019009:Proto-Oncogene Proteins c-kit