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Washington University Experience | NEOPLASMS (EMBRYONAL) | ATRT - Atypical Teratoid Rhabdoid Tumor | 5B1 ATRT (Case 5) H&E 4.jpg
5B1-4 This malignant neoplasm is composed of tumor cells arranged in hypercellular sheets separated by intervening fibrocollagenous septae with vessels, and multiple foci of necrosis. A subset of neoplastic cells has small round cell appearance with minimal cytoplasm, high nuclear-cytoplasmic ratio with hyperchromatic nuclei and nuclear moulding. Another subset has much more abundant eosinophilic cytoplasm with eccentric vesicular nuclei and prominent nucleoli, consistent with a rhabdoid phenotype. While much of the tumor is solid, it shows extensive infiltration into the scant adjacent portions of the cerebellar cortex. Mitotic figures and apoptotic bodies are numerous.
