Prolactinoma, Causes, Signs and Symptoms, Diagnosis and Treatment. 

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Chapters
0:00 Introduction
1:17 Causes of Prolactinoma
1:35 Symptoms of Prolactinoma
2:33 Diagnosis of Prolactinoma
2:54 Treatment of Prolactinoma
A prolactinoma is a benign tumor (adenoma) of the pituitary gland that produces a hormone called prolactin. It is the most common type of functioning pituitary tumor. Symptoms of prolactinoma are due to too much prolactin in the blood (hyperprolactinemia), or those caused by pressure of the tumor on surrounding tissues. Based on size, a prolactinoma can be classified as a microprolactinoma (10 mm diameter) or a macroprolactinoma (10 mm diameter).
Prolactin stimulates the breast to produce milk and has many other functions such as regulation of mood. Hence prolactin levels are usually higher during pregnancy and after childbirth. After delivery of a baby, a mother's prolactin levels come down to normal a few weeks after breastfeeding is discontinued. Each time the milk is dispensed, prolactin levels rise; this process may cycle to maintain milk production. In males, prolactin is responsible for the sexual refractory period after orgasm and excess levels can lead to erectile dysfunction.
The symptoms due to a prolactinoma are broadly divided into those that are caused by increased prolactin levels or mass effect.
Those that are caused by increased prolactin levels are:[3]
Amenorrhea (disappearance of ovulation periods)
Galactorrhea (Milk production; infrequent in men)
Loss of axillary and pubic hair
Hypogonadism (Reduced function of the gonads.)
Gynecomastia (an increase in male breast size)[4]
Erectile dysfunction (in males)
Those that are caused by mass effect are:
Headaches[5]
Vision Changes-visual field deficits, blurred vision, decreased visual acuity[5]
Cranial nerve palsies-especially with invasive tumors or with pituitary apoplexy[5]
Seizures, Hydrocephalus, Unilateral exophthalmos are rare presentations[5]
Pituitary apoplexy is a medical emergency because of spontaneous hemorrhage into the pituitary tumor and presents with severe headaches, vision changes, and panhypopituitarism.[5]
The cause of pituitary tumors remains unknown. It has been shown that stress can significantly raise prolactin levels, which should make stress a diagnostic differential, though it usually is not considered such. Most pituitary tumors are sporadic - they are not genetically passed from parents to offspring.[citation needed]
The majority of moderately raised prolactin levels (up to 5000 mIU/L) are not due to microprolactinomas but other causes. The effects of some prescription drugs are the most common. Other causes are other pituitary tumours and normal pregnancy and breastfeeding. This is discussed more under hyperprolactinaemia.[6]
The xenoestrogenic chemical Bisphenol-A has been shown to lead to hyperprolactinaemia and growth of prolactin-producing pituitary cells.[7] The increasing and prolonged exposure of Bisphenol-A from childhood on, may contribute to the growth of a Prolactinoma.[citation needed]