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Washington University Experience | NEOPLASMS (GLIAL) | Glioblastoma, adenoid pattern | 12C GBM, Adenoid Features (Case 12) CAM 5.2 A

There are rare islands of cytokeratin CAM 5.2 immunoreactive elements. (CAM5.2 IHC) ---- Immunohistochemistry (not shown): The majority of tumor cells are immunoreactive for S-100 protein. Pancytokeratin and EMA are largely unstained or patchy immunoreactive. Immunostains for melanocytic markers, including HMB45 and MelanA are negative. A histochemical stain for reticulin highlights both reticulin-rich and reticulin-poor areas of the tumor, consistent with both gliomatous and sarcomatous elements. The morphologic and immunohistochemical features are consistent with the diagnosis of glioblastoma with sarcomatous and adenoid components (adenoid gliosarcoma). Both the sarcomatous and epithelial elements likely represent foci of metaplasia or heterologous differentiation.

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