Abstract
We describe two cases of peripheral primitive neuroectodermal tumor-Ewing's sarcoma (PNET-ES) arising intracranially in the leptomeninges. Both tumors exhibited a primitive undifferentiated round-cell morphology. Immunohistochemical stains revealed strong membrane expression of CD99 in both cases. A t(11;22)(q24;q12) could be demonstrated with reverse transcriptase-polymerase chain reaction in one case, whereas fluorescence in situ hybridization analysis performed in the second case showed a rearrangement of the EWS gene. The occurrence of PNET-ES at this site is very unusual. Immunophenotypical as well as genetic analysis play a key role in the diagnosis and the distinction from central PNET.
MeSH terms
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12E7 Antigen
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Antigens, CD / analysis
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Cell Adhesion Molecules / analysis
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Child
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Chromosome Aberrations
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Chromosomes, Human, Pair 22 / genetics
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Diagnosis, Differential
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Dura Mater / chemistry
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Dura Mater / metabolism
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Dura Mater / pathology*
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Humans
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Immunohistochemistry
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In Situ Hybridization, Fluorescence
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Male
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Meningeal Neoplasms / genetics
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Meningeal Neoplasms / metabolism
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Meningeal Neoplasms / pathology*
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Neuroectodermal Tumors, Primitive, Peripheral / genetics
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Neuroectodermal Tumors, Primitive, Peripheral / metabolism
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Neuroectodermal Tumors, Primitive, Peripheral / pathology*
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Neurofilament Proteins / analysis
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S100 Proteins / analysis
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Sarcoma, Ewing / genetics
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Sarcoma, Ewing / metabolism
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Sarcoma, Ewing / pathology*
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Synaptophysin / analysis
Substances
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12E7 Antigen
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Antigens, CD
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CD99 protein, human
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Cell Adhesion Molecules
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Neurofilament Proteins
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S100 Proteins
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Synaptophysin