Pineal Gland Cysts.

From Lewis Blevins, MD –  Pineal cysts are seen in about 2% of all MRI’s of the brain. I see them as perhaps more common in pituitary patients simply because I look at the scans with intent.

These are usually quite simple cysts that are a remnant of embryologic development of the pineal gland. Most will never be a problem. Some do, however, increase in size. Think of them as potentially self-filling water balloons of the pineal gland. Even when they increase in size they are rarely a problem.

The pineal gland is in one of those “deep recesses” of the skull. Because of its “protected” status it used to be thought of as the seat of the soul. It is extremely difficult to get to surgically and there are important veins in that area that, if disturbed significantly, can result in death. Thus, neurosurgeons must have an extremely good reason to operate in that area.

Symptoms related to an enlarging or REALLY large pineal cyst may include headaches and other symptoms of hydrocephalus that can occur if the cyst is large enough to obstruct the flow of CSF thru the cerebral aqueduct of Sylvius. Rarely, patients will have unusual eye movement abnormalities that can be brought out by pursuit or tracking eye movements.

Pineal tumors are rare but do occur. One of the common ones is a germinoma that is derived from germ cells. These tumors are usually multifocal and can involve the pituitary stalk presenting with headaches and diabetes insipidus. Serum and/or CSF alpha-fetoprotein and beta-hCG levels are elevated in a number of these patients. Chemotherapy and radiation are the treatments of choice and most patients do not require any surgery. Pinealoblastoma is another tumor of the pineal gland.

So…. what does the pineal gland do? Well. It is “connected” to the optic pathways that convey a “presence or absence” of light. It makes melatonin when the light fades. This may have a lot to do with shutting down the brain so that we can sleep. Such may also somehow work with the arcuate nucleus of the hypothalamus to entrain our daily rhythms of hypothalamic and pituitary function. While we are really not sure of all of its functions I will tell you that plenty of patients with larger pineal cysts, greater than 1 cm, have difficulty falling asleep. Melatonin at bedtime seems to remedy the insomnia. It also helps some normal folks sleep better. Some (including yours truly) find that it works to help reset the circadian variations and permit adjustment and sleep as well as better functioning when crossing 5 or more time zones and, in particular, when traveling from West to East.

Here is a radiology site that has some great images of the pineal gland and different disease states. It looks like a good site to join!

Photo by David Yu – David Yu Photography

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