Case History:
40 year old with hydrocephalus and a third ventricular tumor.
What is this tumor?
A. Ependymoma
B. Choroid Plexus Papilloma
C. Papillary Tumor of the Pineal Region
D. Papillary Glioneuronal Tumor
Correct Answer: C. Papillary Tumor of the Pineal Region
Discussion:
Papillary tumor of the pineal region displays papillary architecture with multilayered epithelium and perivascular pseudorosettes. This tumor stains for CAM5.2, CD56, and MAP2. Glial markers (GFAP and Olig2) are negative. Ki-67 proliferation index is elevated (35%), more than typical of primary pineal parenchymal tumor of intermediate differentiation but less than pineoblastoma.
Reference(s): WHO Classification of Tumours Editorial Board. Central Nervous System Tumours. 5th ed. Lyon, France: International Agency for Research on Cancer; 2021.
Case contributed by: Lisa Godsey, D.O., Neuropathology Fellow