Prolactinoma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Faizan Sheraz, M.D. [2]
Overview
A prolactinoma is a benign tumor (adenoma) of the pituitary gland that produces prolactin. It is the most common type of pituitary tumor. Symptoms of prolactinoma are caused either by hyperprolactinemia or by pressure of the tumor on surrounding tissues. In women, these adenomas are often small (<10 mm). In either sex, however, they can become large enough to enlarge the sella turcica. These adenomas represent the most common hormone-producing pituitary tumors and account for 25% to 41% of tumor specimens.[1] MRI is the most sensitive diagnostic test for detecting pituitary tumors (including prolactinoma). Medical therapy for prolactinoma includes dopamine agonists. Surgery is indicated in patients if medical therapy cannot be tolerated. Transsphenoidal resection of tumor is usually done among patients with prolactinoma.
Historical Perspective
Pituitary tumors were first described by Pierre Marie, a French neurologist.
Classification
Prolactinoma can be classified based upon either size or local invasion. Based on size, a prolactinoma can be classified as a microprolactinoma (<10 mm diameter) or macroprolactinoma (>10 mm diameter).
Pathophysiology
Prolactinoma may occur as part of a hereditary disorder called multiple endocrine neoplasia type 1 (MEN 1). A minority of prolactinomas are associated with multiple endocrine neoplasia type I (MEN I), Carney complex, McCune-Albright Syndrome, MEN like syndrome (CKDN1B loss of function).[2]
Causes
There are no established causes for proloactinoma. The majority of pituitary tumors are sporadic, but a minority of tumors are associated with familial syndromes.
Epidemiology and Demographics
The prevalence of prolactinoma in younger age group is 100 per 100,000 individuals.[3] Pituitary tumors affect approximately 14 out of 100,000 people in United States.
Risk Factors
Common risk factors for the development of prolactinoma include multiple endocrine neoplasia type 1 (MEN 1), Carney complex and McCune-Albright syndrome.
Differentiating prolactinoma from other diseases
Prolactinoma must be differentiated from other causes of hyperprolactinemia such as hypothyroidism, antipsychotics and antidepressants.
Natural History, Complications and Prognosis
If left untreated, 95% of patients with prolactinoma will not show any signs of growth after a 4 to 6 year period. Prognosis is excellent for microprolactinoma. Common complications of prolactinoma include intracranial hemorrhage, osteoporosis and vision loss.
History and Symptoms
Symptoms of prolactinoma include loss of libido, headache, infertility and vision changes.
Physical Examination
Common physical examination findings of prolactinoma include papilledema, visual field defects, cranial nerve palsies.
Laboratory Findings
Laboratory findings consistent with the diagnosis of prolactinoma include elevated prolactin levels and reduced thyroid hormone levels.
CT Scan
On head CT scan, prolactinoma is characterized by enlargement of the pituitary gland.
MRI
MRI may be diagnostic of prolactinoma. Magnetic resonance imaging (MRI) is the most sensitive test for detection of pituitary tumors and determination of their size.
Medical Therapy
Medical therapy for prolactinoma includes dopamine agonists. The goal of treatment is to return prolactin secretion to normal, reduce tumor size, correct any visual abnormalities and restore normal pituitary function.
Surgery
Surgical resection is recommended among patients with failed medical therapy.
References
- ↑ http://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq#link/_169_toc
- ↑ http://radiopaedia.org/articles/pituitary-adenoma
- ↑ Ciccarelli A, Daly AF, Beckers A (2005). "The epidemiology of prolactinomas". Pituitary. 8 (1): 3–6. doi:10.1007/s11102-005-5079-0. PMID 16411062.