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Washington University Experience | NEOPLASMS (EMBRYONAL) | Medulloblastoma, Histologically Defined | Large cell-Anaplastic (LCA) | 15B Medulloblastoma, LCA (Case 15) b-catenin.jpg
Beta catenin immunoreactivity is present in tumor cytoplasm but not nuclei. (B-catenin IHC) ---- FISH assays for C-myc and N-myc amplification and isochromosome 17q show evidence of polysomies (chromosomal gains) of chromosomes 2, 8, and 17 as well as a relative gain of MYC. ---- Not shown:The neoplastic cells are positive for synaptophysin in a weak, membranous distribution throughout; glial fibrillary acidic protein (GFAP) is present in patchy distribution. Nuclear staining with INI-1 is retained. Neurofilament stains entrapped neuropil towards the edges of the tumor. ---- The morphologic and immunohistochemical findings are consistent with a large cell/anaplastic medulloblastoma, WHO grade IV.
