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Washington University Experience | NEOPLASMS (MENINGIOMA) | Rhabdoid | 9B3 Meningioma, rhabdoid (Case 9) 13K EM 3 - Copy

Cell with rhabdoid appearance contain cytoplasmic filamentous inclusions and cytoplasmic cytosomes. ---- Ancillary workup (not shown): Immunohistochemically, the tumor shows positive reactivity to Vimentin and EMA and is negative for cytokeratin. The stain for Ki-67 showed a low proliferation index. Several features in this neoplasm, including focal rhabdoid morphology, sheeting, small cell change, and macronuclei suggests the potential for more aggressive clinical behavior. Therefore, a diagnosis of atypical meningioma was rendered despite the relatively low mitotic count and proliferation index. The morphological and immunohistochemical features are those of a secretory meningioma with focal rhabdoid features, WHO Grade 2.

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