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Pituitary adenoma




Endocrine system

Adrenal gland disorders
Thyroid gland disorders
Parathyroid gland disorders
Pancreatic disorders
Pituitary gland disorders
Gonadal dysfunction
Polyglandular syndromes
Endocrine tumors
Endocrine system pathology review

Pituitary adenoma


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High Yield Notes
7 pages

Pituitary adenoma

9 flashcards

USMLE® Step 1 style questions USMLE

12 questions

USMLE® Step 2 style questions USMLE

6 questions

 A 31-year-old woman comes with her husband to the emergency room complaining of palpitations for the past three weeks. They have started to increase in intensity and frequency over the past two days, and have been accompanied by periods of sweating and tremulousness. Her husband notes that she has been bumping into walls and the edges of tables more recently, and had damaged the fence lining their driveway when backing out in their car three days ago. Her temperature is 36.9°C (98.5°F), pulse is 114/min, respirations are 18/min, and blood pressure is 142/78 mm Hg. Physical examination shows a diffusely enlarged goiter, fine resting tremor in both arms and diaphoresis. An ECG is obtained and shows sinus tachycardia. Which of the following is the most likely diagnosis? 

External References

Content Reviewers:

Rishi Desai, MD, MPH

Pituitary adenoma can be broken down - “adeno” refers to a gland and “oma” refers to a tumor, so pituitary adenoma is a tumor that develops in the hormone-producing cells of the pituitary gland.

Normally, the pituitary is a pea-sized gland, hanging by a stalk from the base of the brain.

It sits just behind the eyes near the optic chiasm, which is where the optic nerves cross.

The anterior pituitary, which is the front of the pituitary gland, contains a few different types of cells, each of which secretes a different hormone.

The largest group of cells are the somatotropes which secrete growth hormone, or GH for short, which goes on to promote tissue and organ growth.

The second largest cell group are the corticotrophs which secrete adrenocorticotropic hormone, or ACTH for short.

ACTH stimulates the adrenal glands to secrete cortisol, a hormone that controls the stress response and metabolic regulation.

A smaller cell group are the lactotrophs which secrete prolactin.

Prolactin stimulates breast milk production, and also inhibits ovulation, which is when an egg cell is released from the ovary, and inhibits spermatogenesis, which is the development of sperm cells.

There are also thyrotrophs which are cells that secrete thyroid stimulating hormone, or TSH which goes on to stimulate the thyroid gland.

And finally, there are also gonadotrophs which secrete two gonadotropic hormones - luteinizing hormone, or LH, and follicle-stimulating hormone, or FSH, both of which go on to stimulate the ovaries or testes.

In pituitary adenomas, one of these cells mutates and becomes neoplastic, meaning that it starts dividing uncontrollably and over time it forms a tumor.

But these cells don’t invade neighboring tissues, so this is considered a benign tumor rather than a malignant one.

Pituitary adenomas can be classified by their size, adenomas smaller than 1cm are called microadenomas, and those larger than 1cm are called macroadenomas.

Macroadenomas are more likely to compress surrounding structures like the meninges, which is the protective layer overlying the brain that typically causes pain when it’s stretched.

Macroadenomas can also compress optic nerves as they cross at the optic chiasm.

That can affect a person’s ability to view things that are in the temporal visual field of both eyes, also called “bitemporal hemianopia”.

Finally, the compression can also affect other healthy pituitary cells and interfere with their ability to make hormones.

Pituitary adenomas that secrete hormones are called functional adenomas, whereas those that don’t are called non-functional adenomas.

Functional pituitary adenomas are divided into a few different types depending on the cells that they arise from and the hormone these cells produce.

The most common type of pituitary adenoma is a prolactinoma which arises from lactotrophs that make prolactin.

In women, excess prolactin causes amenorrhea, which is when there is loss of menstrual bleeding and galactorrhea, which is a milky nipple discharge.

In men, excess prolactin causes a low libido - a low sex drive and gynecomastia or breast enlargement.

The second most common type of pituitary adenoma arises from somatotropes that make growth hormone.

Pituitary adenomas are tumors that occur in the pituitary gland. Pituitary adenomas are generally divided into three categories dependent upon their biological functioning: benign adenoma, invasive adenoma, and carcinomas. Pituitary macroadenomas are the most common cause of hypopituitarism, and in the majority of cases they are non-secreting adenomas.  Hormone secreting pituitary adenomas cause one of several forms of hyperpituitarism. The specifics depend on the type of hormone. Some tumors secrete more than one hormone, the most common combination being GH and prolactin.  A pituitary adenoma may present with visual field defects, classically bitemporal hemianopsia. It arises from the compression of the optic nerve by the tumor. 
  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Harrison's Endocrinology, 4E" McGraw-Hill Education / Medical (2016)
  6. "Management of hormone-secreting pituitary adenomas" Neuro-Oncology (2016)
  7. "The prevalence of pituitary adenomas" Cancer (2004)