A pineal parenchymal tumor is a rare type of brain tumor that originates in the pineal gland, a small endocrine gland located deep within the brain. These tumors can be benign or malignant and are classified into three main subtypes: pineocytoma, pineal parenchymal tumor with intermediate differentiation, and pineoblastoma. The symptoms and treatment options vary depending on the tumor's size, location, and aggressiveness.