title: Benign clear cell (sugar) tumor of the lung. A light microscopic, histochemical, and ultrastructural study with a review of the literature.
abstract: A case of a benign clear cell "sugar" tumor of the lung is reported. Light microscopy showed a uniform proliferation of clear cells filled with abundant glycogen. At the ultrastructural level, tumor cells were rich in free monogranular and rosette-forming glycogen, but no membrane-bound glycogen was demonstrated. Some cells showed plasma membrane interdigitations, microvilli, and macula occludens-type junctions. Many polymorphic secretory and sporadic haloed neurosecretory-like granules were observed, but argyrophil stains as well as a large set of immunohistochemical reactions specific for APUD derivation had negative results. A literature review of this puzzling entity with particular emphasis on the histogenetic hypotheses is presented, and a derivation from epithelial nonciliated bronchiolar (Clara) cells or epithelial serous cells is suggested.
mesh_terms: D000328:Adult; D000368:Aged; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D005260:Female; D006003:Glycogen / Q000032:analysis; D006651:Histocytochemistry; D006801:Humans; D007365:Intercellular Junctions / Q000648:ultrastructure; D008175:Lung Neoplasms / Q000032:analysis / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008871:Microvilli / Q000648:ultrastructure; D008875:Middle Aged
chemical_list: D006003:Glycogen