title: Malignant stromal tumor, so called "gastrointestinal stromal tumor", with rhabdomyomatous differentiation occurring in the gallbladder.
abstract: Gastrointestinal stromal tumors (GISTs) constitute the largest category of primary nonepithelial neoplasms of the gastrointestinal tract. It is extremely rare that this tumor occurs in the bile tract, and only a few cases have been reported. Immunohistochemically, the tumor cells revealed a phenotype similar to Cajal cells, occasionally with differentiation to smooth muscle cells or neural cells. We present a case of malignant stromal tumor similar to GISTs with rhabdomyomatous differentiation of the gallbladder in a 68-year-old woman. The resected tumor was predominantly composed of spindle cells with rhabdomyomatous differentiation. Immunohistochemical study revealed diffuse staining of tumor cells using vimentin despite negative staining for desmin or S-100. This indicated a mesenchymal origin of the cells without smooth muscle or neuronal differentiation. Myoglobin-positive cells, in which phosphotungstic acid hematoxylin staining revealed cross striations of the cytoplasm, suggested rhabdomyomatous differentiation. Diffuse positivity for KIT in the cells suggested that the pathogenesis of this tumor may resemble that of GIST. The tumor may have derived from a mesenchymal stem cell that had undergone partial rhabdomyomatous differentiation.
authors.affiliation: Department of Surgical and Molecular Pathology, Dokkyo University School of Medicine, Shimotsuga, Tochigi, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Furihata
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujimori
authors.forename: Johji
authors.initials: J
authors.lastname: Imura
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ono
authors.forename: Tadashi
authors.initials: T
authors.lastname: Furihata
authors.forename: Mitsugi
authors.initials: M
authors.lastname: Shimoda
authors.forename: Masato
authors.initials: M
authors.lastname: Kato
authors.forename: Junji
authors.initials: J
authors.lastname: Kita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohkura
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kubota
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D002471:Cell Transformation, Neoplastic; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005706:Gallbladder Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D005770:Gastrointestinal Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D006416:Hematoxylin; D006801:Humans; D007124:Immunoenzyme Techniques; D009211:Myoglobin / Q000032:analysis; D010772:Phosphotungstic Acid; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D012207:Rhabdomyoma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D013194:Staining and Labeling; D017154:Stromal Cells / Q000737:chemistry / Q000473:pathology*; D016896:Treatment Outcome; D014746:Vimentin / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D009211:Myoglobin; D014746:Vimentin; D010772:Phosphotungstic Acid; D019009:Proto-Oncogene Proteins c-kit; D006416:Hematoxylin