Pituitary Adenomas

Pituitary adenomas are common, slow-growing and benign tumors of the pituitary gland. Pituitary gland is the master hormone gland of our body located at the base of brain. It regulates the body’s hormones by releasing special hormones into the bloodstream.

Facts about Pituitary adenomas

• Can develop at any age
• Up to 10% of people can have a pituitary adenoma by the time of their death
• Most pituitary adenomas are in the front part (anterior lobe) of the pituitary gland
• Tiny, microscopic pituitary adenomas never grow or cause problems and are accidently diagnosed when a patient undergoes a magnetic resonance imaging (MRI) scan of the brain for another reason

Types of Pituitary adenomas

Pituitary adenomas are classified according to their size, aggressiveness and whether they produce hormones.

Classification according to size:  

• Micro adenoma: Pituitary tumor less than 10 mm in diameter in size
• Macro adenoma: Pituitary tumor equal to or larger than 10 mm in size

Classification according to production of hormones:  

• Secreting or functioning or endocrine-active tumors: These tumors produce too much of any one of the hormones. Examples of functional adenomas include:
• Prolactinoma, a tumor that overproduces prolactin
• Acromegaly (adults) gigantism (child), caused by an excess growth hormone
• Cushing's disease, caused by a pituitary tumor stimulating an overproduction of cortisol 
• Thyrotropinoma caused by excessive TSH hormone production   
• Non-secreting or non-functioning or endocrine-inactive pituitary tumors: These tumors produce more than one type of hormone but do not do not make extra hormone.

Classification according to aggressiveness of tumor

• Benign (noncancerous): Nearly all pituitary adenomas are benign (noncancerous) and slow growing.
• An atypical pituitary adenoma: It is a rarer type, grows more quickly and is more likely to recur.
• Pituitary carcinomas (a malignant tumor): Pituitary carcinomas (a malignant tumor) spread to other parts of the body, and are extremely rare.

Cause of Pituitary adenomas

Pituitary adenomas are not known to be associated with any specific cause and occur spontaneously. They are not inherited but there are some cases of familial pituitary tumors. Following factors may increase the risk of pituitary adenoma:

• Gigantism  
• Young onset of acromegaly
• Multiple endocrine neoplasia type 1 (MEN 1)  

Symptoms of Pituitary adenoma

The symptoms depend upon the size, nature and hormone production of tumor. It includes:

• Headaches
• Vision problems
• Blurry vision
• Colours not perceived as bright as usual
• Menstrual cycle changes in women
• Mood swings or behaviour changes
• Erectile dysfunction
• Weight change
• Loss of body and facial hair
• Infertility
• Galactorrhoea  
• Reproductive dysfunction
• Hypertension
• Diabetes mellitus
• Cardiovascular disease

Diagnosis of Pituitary adenoma:

Diagnosis requires any or all of the following:

• Medical history
• Physical findings
• Blood and urine tests to measure hormone levels of PRL, GH, IGF-1, free thyroxine, cortisol, and testosterone (in males)
• High-resolution, T1 weighted, gadolinium enhanced MRI
• Computed tomography (CT)

Treatment of Pituitary adenoma:

Treatment is done by specialized endocrinologists and oncologists. It depends upon size, extent and hormone production status of the tumor.

• Endonasal transphenoidal endoscopic surgery
• Medical therapy
• Radiation therapy
• Hormone therapy
• Observation

Authored by Dr. Shyam Sundar K