title: Malignant granular cell tumor: report of a case and review of the literature.
abstract: The histological, immunohistochemical and electron microscopic features of a rare malignant granular cell tumor (GCT) arising in the left radial nerve of a 54-year-old man are reported. Despite a lack of local recurrence following extirpation, the tumor metastasized to the skull five years later. Light-microscopically, both primary and metastatic tumors consisted of markedly atypical or pleomorphic neoplastic cells with abundant cytoplasm containing diastase-resistant periodic acid Schiff reaction-positive granules. These tumor cells were arranged in a sheet-like pattern with mitotic figures including atypical ones, and were frequently immunopositive for proliferating cell nuclear antigen and c-MET, the c-met proto-oncogene product. These findings reflect high-grade malignancy of the present tumor. In addition, the tumor cells were positive for S-100 protein and neuron-specific enolase. Ultrastructurally, a large number of intracytoplasmic granules featuring secondary lysosomes as well as long interdigitating cytoplasmic processes, intercellular intermediate junctions, discontinuous basal lamina-like structures, and stromal long-spacing collagen were observed. These findings indicated schwannian differentiation of the present tumor. In addition, based on a review of previously reported cases, the overall clinicopathological characteristics of malignant GCT were summarized.
authors.affiliation: Department of Pathology, Kochi Medical School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sonobe
authors.forename: J
authors.initials: J
authors.lastname: Iwata
authors.forename: M
authors.initials: M
authors.lastname: Furihata
authors.forename: T
authors.initials: T
authors.lastname: Moriki
authors.forename: Y
authors.initials: Y
authors.lastname: Ohtsuki
mesh_terms: D002467:Cell Nucleus / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D016586:Granular Cell Tumor / Q000378:metabolism / Q000556:secondary*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010503:Periodic Acid-Schiff Reaction; D010524:Peripheral Nervous System Neoplasms / Q000378:metabolism / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D000090063:Proto-Oncogene Mas; D011826:Radial Nerve / Q000473:pathology*; D009418:S100 Proteins / Q000378:metabolism; D012888:Skull Neoplasms / Q000556:secondary*
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase