title: Clear cell tumor of the lung: an immunohistochemical and ultrastructural study supporting a pericytic differentiation.
abstract: Clear cell tumor ("sugar tumor") of the lung is a rare benign lesion with unclear histogenesis. It is composed of large cells with a clear cytoplasm rich in glycogen, blended with an abundant network of sinusoid-type vessels. We report two cases of sugar tumor, one of these lacking clearly demonstrable glycogen storage. In both, the tumor cells lacked keratin expression and were positive for vimentin and HMB 45, an antibody recognizing perivascular or myoid cell proliferation such as lymphangioleiomyomatosis and angiomyolipoma. The tumor cells were also immunoreactive for an endothelial cell marker, CD 34, but negative for Factor VIII or smooth muscle actin. Intercellular deposition of basal-like material was immunostained with Type IV collagen. At ultrastructural examination of one of these cases, tumor cells showing features of pericytes or poorly differentiated perivascular leiomyocytes encased in basement material were observed in close association with endothelial cells; their cytoplasm contained numerous membrane-bound glycogen and pinocytic vesicles. We conclude that on the basis of immunohistochemical and ultrastructural phenotype, sugar tumor presents pericytic features and that glycogen storage is not a constant feature of these benign tumors.
authors.affiliation: Service de Pathologie Cellulaire, Centre Hospitalier Universitaire A. Michallon, La Tronche, France.
authors.forename: S
authors.initials: S
authors.lastname: Lantuejoul
authors.forename: S
authors.initials: S
authors.lastname: Isaac
authors.forename: N
authors.initials: N
authors.lastname: Pinel
authors.forename: A
authors.initials: A
authors.lastname: Negoescu
authors.forename: B
authors.initials: B
authors.lastname: Guibert
authors.forename: E
authors.initials: E
authors.lastname: Brambilla
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D000368:Aged; D018952:Antigens, CD34 / Q000096:biosynthesis; D000951:Antigens, Neoplasm / Q000096:biosynthesis; D002454:Cell Differentiation; D003094:Collagen / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008562:Membrane Glycoproteins; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000648:ultrastructure; D009363:Neoplasm Proteins / Q000096:biosynthesis; D011506:Proteins; D014746:Vimentin / Q000096:biosynthesis; D058951:gp100 Melanoma Antigen
chemical_list: D018952:Antigens, CD34; D000951:Antigens, Neoplasm; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D011506:Proteins; D014746:Vimentin; D058951:gp100 Melanoma Antigen; D003094:Collagen