The pituitary gland is a small, pea-sized organ in the brain that produces hormones that affect many other glands in the body. Although rare, most pituitary tumors are noncancerous. However, because of the location of the pituitary gland, at the base of the skull, many pituitary tumors will press against the optic nerves, causing vision problems.

Cancerous pituitary tumors, or pituitary carcinomas, are rare and generally found in older persons. Pituitary carcinomas often make hormones, just as many benign pituitary tumors do. In most cases, the only definitive way to differentiate a cancerous pituitary tumor from a benign one is when the tumor spreads to another part of the body several years later.

Symptoms vary depending upon what type of tumor is growing and what area of the pituitary gland is affected. Pituitary tumors can lead to symptoms that are caused by an excess or a reduced production of pituitary hormones.