title: Gastric tumors in patients with pulmonary chondroma or extra-adrenal paraganglioma: an ultrastructural study.
abstract: The histogenesis of a distinctive metastasizing intramural gastric tumor found in patients with extra-adrenal paragangliomas, pulmonary chondromas, or both, is unknown. By light microscopy, it has appeared to be of smooth-muscle derivation, and it has been interpreted as being epithelioid leiomyosarcoma. For further clues to its nature, we studied three examples by electron microscopy (two obtained from patients with extra-adrenal paragangliomas and one from a patient with pulmonary chondroma). Ultrastructurally, they were characterized by interdigitating cytoplasmic processes, plasma membrane-associated dense patches, an incomplete basement membrane, junctional complexes, randomly oriented filaments without periodicity, cytoplasmic dense bodies, pinocytotic vesicles, clustering of mitochondria, and rare cilia-features of normal smooth muscle or of smooth-muscle tumors with classic histologic patterns. Thus, the findings suggest that the three tumors we studied are of smooth-muscle derivation.
mesh_terms: D000293:Adolescent; D000328:Adult; D002467:Cell Nucleus / Q000648:ultrastructure; D002648:Child; D002812:Chondroma; D003599:Cytoskeleton / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008175:Lung Neoplasms; D008928:Mitochondria / Q000648:ultrastructure; D009130:Muscle, Smooth / Q000648:ultrastructure; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D010235:Paraganglioma; D013274:Stomach Neoplasms / Q000648:ultrastructure*