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Washington University Experience | NEOPLASMS (PINEAL) | Pineocytoma | 5B1 Pineocytoma (Case 5) H&E 3.jpg
5B1-6 This neoplasm consists largely of small, uniform tumor cells with round-to-oval nuclei, dense, finely-speckled chromatin, inconspicuous nucleoli, modest amounts of eosinophilic cytoplasm, and poor cellular demarcation. These cells are generally arranged in 'pineocytomatous' rosettes, with tumor cell nuclei appearing to surround small areas of delicate neuropil, and in similar pseudorosettes that surround a centrally-located small blood vessel. Occasional large cells, with bizarre, hyperchromatic, irregularly-shaped nuclei, are also present, as are a few focal areas containing cells with a ganglionic or neuronal appearance. Mitotic figures are not observed. (H&E)
