GERMINAL neoplasms of the central nervous system differ from the epidermoid-dermoid group of tumors within the central nervous system not only in respect to their location, but also in their genesis. The former are most often found in the region of the pineal gland. The pineal gland is generally involved or destroyed by the neoplasm, and on this basis, it was assumed that the teratomas in this region arise from the pineal gland. This cannot be true in those instances where the pineal gland is not involved or where the germinal neoplasm arises in a region away from the pineal gland. Nevertheless, many teratomas in such areas have been described as primary pineal neoplasms (ectopic pinealomas).
The true pinealoma (from pineal tissue proper) is actually less common than the germinal neoplasms of the pineal and parapineal region. McGovern stated that of 236 pineal tumors recorded up to the end of