Page Menu

What Causes Pituitary Microadenoma?

A pituitary microadenoma is a pituitary adenoma (tumor) that is smaller than 1 centimeter. These tumors form on the pituitary gland and are the most common form of pituitary tumor. Pituitary microadenomas develop when DNA mutations cause cells in the pituitary gland grow and divide uncontrollably. Experts are not entirely sure what causes these genetic mutations to happen. A small percentage of pituitary tumors run in families, but most cases do not have any obvious hereditary factor. That said, individuals with a multiple endocrine neoplasia, type I (a hereditary condition commonly referred to as MEN I) may be at an increased risk of pituitary tumors and other tumors of the endocrine system.

Symptoms of a pituitary microadenoma

Many pituitary tumors are not cancerous and do not progress to cause symptoms. However, pituitary microadenomas are more likely to be functioning tumors, which means that they produce hormones. The hormone imbalance that can be caused by pituitary microadenomas can produce a number of symptoms, often resulting in the diagnosis of the tumor. Below are some of the common hormone imbalances caused by pituitary microadenomas and the symptoms they produce:

  • High levels of growth hormones – Often leads to increased swelling and joint pain
  • High levels of ACTH (steroid hormones) – Can cause Cushing’s disease, resulting in weight gain, swelling, hair growth, vision changes, high blood pressure and decreased sex drive
  • High levels of prolactin (luteotropic hormone) – Results in osteoporosis, decreased sex drive, infertility, changes to the menstrual cycle in women and breast growth and erectile dysfunction in men

Pituitary microadenoma treatment

The most appropriate form of treatment for pituitary microadenomas depends on whether or not the tumor is functional and which hormone it produced if it is functional. Based on those and other individual factors, treatment for a pituitary microadenoma may include:

  • Surgery to remove the tumor
  • Radiation therapy to destroy the tumor if surgery isn’t an option
  • Medication to stop excess hormone production

If you have questions about your pituitary microadenoma and the treatment options available to you, we encourage you to request an appointment at Moffitt Cancer Center. To do so, call 1-888-663-3488 or submit a new patient registration form online. Referrals are not required.