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Washington University Experience | NEOPLASMS (EMBRYONAL) | Medulloblastoma, Histologically Defined | Large cell-Anaplastic (LCA) | 1A1 MB LCA (Case 1) H&E 1

Case 1 History ---- [11yo male with a posterior fossa mass. Operative procedure: Excision] ---- 1A1-5 This is a highly cellular primitive appearing neoplasm with moderate to marked nuclear pleomorphism. In some areas, the tumor resembles a classic medulloblastoma, composed of small cells with high nuclear/cytoplasmic ratios and delicate fibrillary neuropil in the background. In most areas, however, the tumor cells appear somewhat enlarged with vesicular to irregular hypochromatic nuclei and prominent nucleoli. There is prominent cell wrapping and occasional multinucleated giant cells are seen. The mitotic index is brisk and there are foci of apoptotic lakes. Scattered atypical mitoses are also evident and there are foci of tumor necrosis.

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