Prolactinoma
Endoscopic Pituitary Surgery
Prolactinoma
Prolactin is a hormone produced by the pituitary gland that stimulates breast milk production in pregnant and nursing women and its level falls with cessation of breast-feeding. Very high levels of prolactin (hyperprolactinemia) can cause hormonal disturbances including milk production to occur in men as well as in non- pregnant women.
Prolactinomas, the most common type of pituitary adenomas (30% of all pituitary adenomas), cause excess secretion of the hormone prolactin (PRL). These are 5 times more common in women and it occurs in the third and fourth decades of life.
Prolactinomas cause symptoms either due to the hormonal effects of excess PRL or due to the pressure effect on the pituitary gland and the critical neurovascular structures that surround it such as the optic nerves. The hormonal symptoms resulting from hyperprolactinemia are different in males than in females.
Prolactinomas are the most common cause of hyperprolactinemia. Prolactin secretion in the pituitary is normally suppressed by the brain chemical dopamine. Use of certain drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete prolactin.These include Metoclopramide, or anti-depressants such as Fluoxetine, an underactive thyroid gland (hypothyroidism), some growth hormone (GH)-producing tumours and other types of pituitary tumours that arise in or near the pituitary gland- as those may compress the pituitary stalk and block the flow of dopamine from the brain to the prolactin-secreting cells causing hyperprolactinemia, this is commonly known as “stalk effect”.
Symptoms :
In women, abnormal milk flow from the breast in a woman who is not pregnant or nursing (galactorrhea), breast tenderness, decreased sexual interest, headache, infertility, stopping of menstruation (amenorrhoea) not related to menopause, and vision changes
In men, decreased sexual interest, enlargement of breast tissue (gynecomastia), headache, impotence, infertility and vision changes.
Symptoms caused by pressure from a larger tumour may include headache, lethargy, nasal drainage, nausea and vomiting, problems with the sense of smell and vision changes (double vision, ptosis and visual field loss).
If untreated, prolactinomas may enlarge, producing mass effects such as visual field deficits or total blindness, cranial nerve palsies, hydrocephalus, pituitary apoplexy, and hypopituitarism. The effects of prolonged untreated hyperprolactinemia can include hypogonadism, infertility and osteoporosis.
Diagnosis :
- A thorough medical history and neurological examination.
- Prolactin level in blood.
- Other pituitary hormones.
- MRI scan.
- Neuroopthalmological assessment of visual acuity (VA) and visual fields (VF).
Treatment :
Treatment is indicated if mass effects from the tumor, significant effects from hyperprolactinemia, or both are present. The goal of treatment is to return prolactin secretion to normal, reduce tumour size, correct any visual abnormalities, and restore normal pituitary function. Treatment options include medical, surgical and pituitary irradiation.
In Prolactinoma patients with minimal symptoms or no symptoms, the patient can be monitored closely with serial estimations of serum PRL levels combined with imaging studies at yearly intervals.
As dopamine is the chemical that normally inhibits prolactin secretion by the pituitary gland, drugs that act like dopamine or dopamine agonists e.g. Bromocriptine , pergolide , and cabergoline are used in the treatment of prolactinomas. Once started, these drugs must be continued for life as prolactin levels often rise again in most people when the drug is discontinued and failure is more likely with large prolactinomas. Using bromocriptine or one of the other drugs over time can reduce the chance of a cure using surgical removal. Therefore, if surgery is to be performed, its best timing is during the first six months of using medical therapy.
Surgical treatment is reserved for women who have a microaprolactinoma, desire pregnancy and cannot tolerate or do not wish to take bromocriptine or one of the other drugs, patients who do not respond to medical treatment, or those who show progression of symptoms after an initial response to medical treatment.
The use of radiotherapy for prolactinomas has declined in recent years due to the remarkable effectiveness of other treatments such as medications and surgery, hence it is usually reserved for patients who have persistent and progressive symptoms that were not cured by medications or surgery, or patients who cannot tolerate them.
Even with successful treatment, careful monitoring of clinical signs and symptoms, serial measurements of serum PRL levels and pituitary imaging on yearly basis for the rest of the follow-up period are essential.
The Heart Of Clinic
Dr. C. Rayappa MBBS, DLO, FRCS(Edin)
SENIOR CONSULTANT
+91 44 3315 1105
Dr. C. Rayappa graduated from Madras Medical College, Chennai, India in 1982. He completed his post graduation in Otolaryngology (ENT)