Q. I have a friend who has asked me to search the Internet for information about "penal or penel cysts," located in the brain or head area. I have had no luck. Could you help?
-- R.M., Middletown, N.J.
A. Your friend is probably talking about cysts on the pineal gland in the brain.
The pineal gland, or pineal body, is a small, flattened cone-shaped organ located in the lower-middle part of the brain. It is much more active in amphibians and lower mammals; in humans, it ceases to grow much beyond childhood.
The human pineal gland synthesizes the hormone melatonin, which is considered to be involved in the regulation of sleep, mood, puberty and ovarian cycles. Essentially, the function of the pineal gland is to control the body's biological clock.
Tumors of the pineal region, either benign or malignant, are rare, accounting for less than 1 percent of tumors of the head. In one study, more than one-third of pineal tumors treated were found to be benign. However, about one-quarter of pineal glands have cysts on them.
Tumors on the pineal gland can suppress the synthesis and secretion of melatonin, which can result in precocious puberty. Other symptoms of pineal gland tumors include impaired upward gaze and disturbances of gait.
Growths on the pineal gland, even benign tumors and cysts, can affect the body in another way. If tumors or cysts continue to grow in the confined space occupied by the pineal gland, the increased volume of the tissue can obstruct drainage of fluid from the central nervous system.
This cerebrospinal fluid obstruction can result in increased intracranial pressure, which can lead to hydrocephalus and compression of central nervous system tissue. This compression can in turn result in changes in vision and mental status.
Diagnosis to differentiate tumors from cysts can be made by imaging studies; MRIs are especially effective.
Surgical removal of pineal cysts is recommended when symptoms are seen. Treatment involves total or partial removal of the tumor or cystic tissue by surgery and possibly treatment with radiation and chemotherapy, depending on the type and extent of abnormal growth. Increased cranial pressure can be relieved by use of a shunt to reduce the amount of cerebral spinal fluid.