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Washington University Experience | NEOPLASMS (PINEAL) | PPTID (Pineal Parenchymal Tumor Intermediate Differentiation) | 3B1 PPTID (Case 3) H&E 1

3B1-5 This is a moderately cellular neoplasm arranged in a rosetted architecture. These rosettes have fibrillary meshwork in the center and are surrounded by cells containing elongate to oval nuclei ("pineocytomatous rosettes'). There is mild to moderate pleomorphism. Mitotic activity is variable. In most areas, mitotic figures appear at moderate density, on the order of 4/10 HPF; however, in approximately 5-10% of the sampled material, mitotic density reaches 6/10HPF and many mitotic figures are atypical or bizarre. There is no evidence of necrosis.

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