Information on the following diseases can be found in the Related Disorders section of this report:

• Chiari-Frommel syndrome
• Ahumada-del Castillo syndrome
• hypothyroidism

Many of the symptoms of prolactinoma are caused by an excessive amount of prolactin in the blood (hyperprolactinemia). In women, prolactinoma is characterized by irregular menstrual periods (amenorrhea), infertility and production of breast milk in women who are not pregnant (galactorrhea). Some women experience diminished sexual desire or painful intercourse. The most common symptom in men is impotence.

Some symptoms such as headaches and vision abnormalities are caused by pressure from the pituitary tumor on other tissues in the brain.

The cause of pituitary tumors is unknown. Most pituitary tumors are sporadic and not associated with genetic factors that are inherited or can be passed on to children.

Pituitary tumors that produce enough prolactin to affect health occur in approximately 14 out of 100,000 people.

Symptoms of the following disorders can be similar to those of prolactinoma. Comparisons may be useful for a differential diagnosis.

Chiari-Frommel syndrome is a rare endocrine disorder that affects women who have recently had a child (postpartum) and is characterized by the production of breast milk (lactation), lack of ovulation (anovulation), and the absence of regular menstrual periods (amenorrhea). These symptoms persist long after childbirth. The absence of normal hormonal cycles may result in a reduction in the size of the uterus (atrophy). Other symptoms may include emotional distress, anxiety, headaches, backaches, abdominal pain, and occasionally obesity. (For more information on this disorder, choose "Chiari-Frommel" as your search term in the Rare Disease Database.)

Ahumada-del Castillo syndrome is a rare endocrine disorder characterized by the abnormal function of the hypothalamus and pituitary glands affecting the secretion of hormones. This disorder affects only women and is not related to pregnancy. The two major symptoms of this disorder include the production and expression of milk from the breasts not associated with childbirth or nursing, and the absence of regular menstruation. There is normal development of secondary sexual characteristics. (For more information on this disorder, choose "Ahumada-del Castillo" as your search term in the Rare Disease Database.)

Hypothyroidism is a condition characterized by abnormally decreased activity of the thyroid gland and deficient production of thyroid hormones. The thyroid gland secretes hormones that play an essential role in regulating growth, maturation, and the rate of metabolism. Specific symptoms and findings associated with hypothyroidism may be variable, depending upon the age at symptom onset, the degree of thyroid hormone deficiency, and/or other factors. In many adults with hypothyroidism, the condition may be characterized by generalized fatigue and lack of energy (lethargy), muscle weakness and cramping, dryness of the skin and hair, incomplete or infrequent passing of stools (constipation), sensitivity to cold, and other symptoms. Individuals with hypothyroidism sometimes have hyperprolactinemia that can cause reproductive disorders. (For more information on this disorder, choose "hypothyroidism" as your search term in the Rare Disease Database.)

Many drugs are known to cause hyperprolactinemia, including dopamine-receptor antagonists (phenothiazines, butyrophenones, thioxanthenes, risperidone, metoclopramide, sulpiride pimozide), dopamine-depleting agents (methyldopa, reserpine) and others such as isoniazid, danazol, tricyclic antidepressants, monoamine antihypertensives, verapamil, estrogen, antiandrogens, cyproheptadine, opiates, H2-blockers and cocaine.

Prolactinoma is treated with medications that act like dopamine (dopamine agonists) such as bromocriptine and cabergoline because dopamine inhibits prolactin secretion. These medications reduce the size of the tumor and reduce the amount of prolactin secretion in approximately 80% of patients. Surgery may be recommended if medical therapy is not effective. Pituitary tumors recur after surgery in some affected individuals.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

Biller BM, Luciano A, Crosignani PG, et al. Guidelines for the diagnosis and treatment of hyperprolactinemia. J Reprod Med. 1999 Dec;44(12 Suppl):1075-84.

Blackwell RE. Hyperprolactinemia. Evaluation and management. Endocrinol Metab Clin North Am. Mar 1992;21(1):105-24.

Conner P, Fried G. Hyperprolactinemia; etiology, diagnosis and treatment alternatives. Acta Obstet Gynecol Scand. Mar 1998;77(3):249-62.

Davies PH. Drug-related hyperprolactinaemia. Adverse Drug React Toxicol Rev. Jun 1997;16(2):83-94.

Schlechte JA. Long-term management of prolactinomas. J Clin Endocrinol Metab. August 2007;92(8):2861-5.

Serri O, Chik CL, Ur E, Ezzat S. Diagnosis and management of hyperprolactinemia. CMAJ. Sep 16 2003;169(6):575-81.

Valdemarsson S. Macroprolactinemia. Risk of misdiagnosis and mismanagement in hyperprolactinemia. Lakartidningen. 2004;101(6):458-65.