Pineal Gland - Pathology

Pathology

All tumors involving the pineal gland are rare; most (50% to 70%) arise from sequestered embryonic germ cells. They most commonly take the form of so-called germinomas, resembling testicular seminoma or ovarian dysegerminoma. Other lines of germ cell differentiation include embryonal carcinomas; choriocarcinomas; mixtures of germinom, embryonal carcinoma, and choriocarcinoma; and, uncommonly, typical teratomas (usually benign). Whether to characterize these germ cell neoplasms as pinealomas is still a subject of debate, but most pinealophiles favor restricting the terms pinealoma to neoplasms arising from the pineocytes.

A pineal tumor can compress the superior colliculi and pretectal area of the dorsal midbrain, producing Parinaud's syndrome. Pineal tumors also can cause compression of the cerebral aqueduct, resulting in a noncommunicating hydrocephalus.