Tumor Types > Pineal Tumors
Pineal region tumors come from the pineal gland, a gland which doesn't do very much at all in humans. The pineal gland is located at the posterior extent (back) of the third ventricle and extends over the tectal plate of the midbrain. This structure controls eye movements, particularly the ability to look upwards. In addition, the tectal plate sits over the Sylvian Aqueduct - a thin tube within the midbrain through which ventricular fluid flows. Pressure on the tectal plate results in obstruction of the aqueduct, as well as a build up of ventricular fluid in the lateral and third ventricles. This is called obstructive hydrocephalus, a condition which can cause headaches, coma and eventually death if left untreated.
There are a number of different cells in the pineal gland which can grow into a tumor. The pinealocyte, the cell with the greatest number in the gland, can transform into a pinealocytoma (pinealoma) or to the malignant pinealoblasoma. Primative cells within the pineal gland can give rise to germinomas or teratomas or so-called yolk sac tumors. Teratomas are usually benign but can turn into teratocarcinomas which can be highly malignant. Finally, the pineal gland has glial cells, and these can develop into astrocytomas, oligodendrogliomas, or mixed gliomas. Pilocytic astrocytomas can develope in this area also.
Symptoms The symptoms of a pineal tumor are diplopia (loss of ability to look upward) and symptoms related to hydrocephalus and increased intracranial pressure. These lesions may be detected on CT scanning, and seen even better on MRI which defines the tumor and the surrounding anatomy more clearly. Germinomas are almost always found in male patients. A tissue diagnosis with tissue obtained at surgery is required for proper and effective treatment.
Pineal tumors are in contact with the spinal fluid and therefore can seed the CSF. Malignant tumors such as pinealoblastomas, germinomas, yolk sac tumors and malignant teratomas can drop metastases in the CSF, giving the tumor cells access to the spine and other parts of the brain. Because of the possibility of metastasis, these lesions must be treated with chemothereapy or cranio-spinal irradiation therapy following surgery.