The pituitary gland or “master gland” is the pea-sized structure at the base of the brain. The pituitary gland controls the adrenal glands, skin, brain and immune system, ovaries or testes, muscles, bones, uterus mammary glands, thyroid, and kidneys. The gland is surrounded by a bony container called the sella turcic, which protects it but does not leave much room for swelling or for a tumor to grow. A pituitary tumor can cause symptoms related to the overproduction or underproduction of hormones in any of the systems the gland regulates.
1. Functioning vs. Nonfunctioning Tumors
Pituitary tumors are typically noncancerous or benign. However, they are divided into two categories: functioning and nonfunctioning. Functioning tumors produce a hormone on their own. Nonfunctioning tumors do not produce hormones. Any condition that causes the enlargement of the pituitary gland can cause the gland to press against the bony structure surrounding it. This pressure can lead to overproduction of one type of hormone and underproduction of another. As such, pituitary tumors can produce different symptoms depending on the structures to which it is causing compression. It can also mimic some organ diseases such as adrenal, thyroid, or pancreas malfunction.