PPTID

Pineal parenchymal tumor of intermediate differentiation (PPTID), as the name suggests, falls between Pineocytoma (WHO Grade I, well-differentiated) and Pineoblastoma (WHO Grade IV, poorly-differentiated) in appearance and biologic behavior. They are considered WHO Grade II/III tumors and make up between 10% to 30% of pineal parenchymal tumors. They are highly cellular and composed of sheets of tumor cells with bland nuclear features. Mitotic activity is low and pineocytomatous rosettes are absent or rare. The survival in PPTID is better than in Pineoblastoma.