Stromal cells in hemangioblastoma: neuroectodermal differentiation and morphological similarities to ependymoma.
The histogenesis of stromal cells in hemangioblastoma is inconclusive despite a long-term controversy. An immunohistochemical and ultrastructural study was conducted for 17 cases of cerebellar hemangioblastoma. A wide range of immunohistological markers, targeting epithelial, mesenchymal, endothelial and neuroectodermal tissues, was used. In all cases, the microscopic hallmark characterizing hemangioblastomas, that is, lipid-containing stromal cells and a fine capillary network, known as a reticular variant, was noted. Stromal cells showed a variable immunoreactivity for neuroectodermal markers, such as S-100 protein, CD56, CD57, CD99, and neuron-specific enolase. This result, in conjunction with the absence of immunoreactivity for epithelial, mesenchymal, and endothelial markers, likely suggests neuroectodermal differentiation of stromal cells. In three cases, another component, known as a cellular variant, where epithelioid tumor cells were arranged in nests encircled by capillaries and/or in pseudorosette-like structures, was noted. Glial fibrillary acidic protein-immunoreactivity, which was totally absent in cases only showing the reticular pattern, was noted in two of them, suggesting a distinctive sign of glial differentiation in a proportion of hemangioblastomas. Ultrastructurally, microvilli-like projections in intracytoplasmic vacuoles were demonstrated in stromal cells. This result, taken together with the neuroectodermal hypothesis of stromal cells, suggests that hemangioblastomas may occasionally exhibit morphological similarities to ependymomas.
Department of Pathology, Saitama Medical School, Saitama, Japan. ishizawa@saitama-med.ac.jp
Keisuke
K
Ishizawa
Takashi
T
Komori
Takanori
T
Hirose
D000071443:12E7 Antigen; D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis; D018959:CD57 Antigens / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D002454:Cell Differentiation; D002528:Cerebellar Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D002648:Child; D003598:Cytoskeletal Proteins; D003937:Diagnosis, Differential; D004806:Ependymoma / Q000473:pathology; D005260:Female; D018325:Hemangioblastoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D017599:Neuroectodermal Tumors / Q000473:pathology; D010750:Phosphoproteins / Q000032:analysis; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis; D017154:Stromal Cells / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000032:analysis; D014746:Vimentin / Q000032:analysis; D000099149:Ezrin
D000071443:12E7 Antigen; D015703:Antigens, CD; D019002:CD56 Antigen; D018959:CD57 Antigens; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D010750:Phosphoproteins; D010751:Phosphopyruvate Hydratase; D009418:S100 Proteins; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D014746:Vimentin; D000099149:Ezrin; C061828:CD99 protein, human