A pituitary microadenoma is a noncancerous growth in the pituitary gland that is less than 10 mm in size. Symptoms of the condition may include such things as headaches, vomiting, vision problems and dizziness. Treatment options can include surgery, drug therapy, and radiation therapy.
What Is a Pituitary Microadenoma?A pituitary microadenoma is a benign (non-cancerous) growth in the pituitary gland that is smaller than 10 millimeters in size. A pituitary microadenoma differs from a pituitary macroadenoma, which is 10 millimeters or larger. Most pituitary tumors are microadenomas.
Understanding the Pituitary Gland
The pituitary gland, which is sometimes called the master gland, plays an important role in regulating growth and development, metabolism, and reproduction. The pituitary gland produces a number of key hormones, including:
- Prolactin, which stimulates the breasts to produce milk during pregnancy. After delivery of the baby, a mother's prolactin levels fall unless she breastfeeds her infant. Each time the baby nurses, prolactin levels rise to maintain milk production.
- Thyrotropin, which signals the thyroid gland to produce thyroid hormone.
- Growth hormone, which regulates growth.
- ACTH (adrenocorticotropin), which stimulates the adrenal glands to produce cortisol.
- Luteinizing hormone and follicle-stimulating hormone, which regulate ovulation and estrogen and progesterone production in women, and sperm formation and testosterone production in men.
Types of Pituitary Microadenomas
There are several types of pituitary microadenomas, classified based on whether they produce hormones or not. A pituitary microadenoma that makes one or more of the pituitary hormones is called a functioning pituitary microadenoma. A pituitary microadenoma that does not make hormones is called a nonfunctioning pituitary microadenoma.
Each type of functioning pituitary microadenoma causes different symptoms, depending on the type of hormone that is being produced. Examples of functioning pituitary microadenomas include:
- Prolactin-producing microadenomas
- Growth hormone-producing microadenomas
- ACTH-producing microadenomas
- Thyroid hormone-producing microadenomas.