Pituitary Tumors

Adenoma gland cell tumors are among the most common, producing symptoms by pressing on vital structures around them or producing excess amounts of hormones which disrupt the normal function of the body. Assessing true relationships between apparent risk factors and incidence of these tumors is difficult due to long incubation periods, as a result risk factors may be a result of preclinical tumor, most of these tumors are of unknown etiology.

Family history of pituitary tumors is not common, they are mostly associated with MEN1 syndromes, caused by mutations, which has 50% chance of being transmitted to offspring. Another rare condition due to changes in CDKN1B genes is MEN4. McCune-Albright syndrome can cause some pituitary tumors, as well as bone defects due to GNAS1 gene mutations. Carney syndrome is caused by genetic changes, of one them being in the PRKAR1A gene. A small percentage is linked to germline mutations in aryl hydrocarbon receptor interacting proteins, specifically growth hormone producing adenomas.

• Post menopausal periods occuring one year after menopause has been found to be a risk factor, especially if the ovaries have been removed.
• Hormone replacement therapy use for less than a year is linked to three times higher risks.
• Risks are higher in women who very young at their first childbirth under the age of 20.
• History of family breast cancer increases risk of pituitary tumors in offspring.
• History of adrenal, thyroid, parathyroid, and colorectal tumor increase risks, which may be due to MEN1 syndrome.
• Twin pregnancy history is associated with higher risk of pituitary tumor.
• Smoking has very negative associations.
• History or other tumors, previous head injury, and epilepsy have negative associations with pituitary tumors.

Estrogen exposure has been linked negatively in almost every study because estrogen stimulates growth of prolactin secreting lactotroph cells in the pituitary gland.

Parity has been linked negatively with risk of these tumor, which may possibly explain why subclinical pituitary tumors impact fertility.

Patients with allergies taking regular medication have decreased risk of developing these tumors, constant immune system activity may account for the reduction, or possible undocumented effects of the medications, raised tumor antigens may spur the immune system to eliminate tumor cells, lowering incidence.