• Clinical science

Pituitary adenoma

Summary

Pituitary adenomas are benign tumors that often arise sporadically from the anterior pituitary gland. They are classified based on their size as microadenomas or macroadenomas, and whether they produce hormones as secretory (functional) and nonsecretory (nonfunctioning) adenomas. Secretory adenomas produce the pituitary hormone of the corresponding cell type, which results in a state of hyperpituitarism. Nonsecretory macroadenomas, however, destroy the surrounding normal pituitary tissue and result in hypopituitarism. Additionally, large macroadenomas compress the optic chiasm and can thus present with signs of mass effect such as bitemporal hemianopsia. The investigation of choice is a contrast-enhanced cranial MRI, which reveals an intrasellar mass. Assays of pituitary hormones are used to evaluate the patient for endocrine abnormalities, and perimetry is required to document visual field defects. Transsphenoidal surgical resection is the first-line therapy for most pituitary adenomas; however, nonsecretory microadenomas generally only require follow-up, and prolactin-producing pituitary adenomas (prolactinomas) are best treated with dopamine agonists (e.g., cabergoline, bromocriptine). Pituitary irradiation is indicated only if the pituitary adenomas recur and/or if surgical therapy is contraindicated.

Epidemiology

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Pathophysiology

Secretory pituitary adenomas
Origin

Relative frequency (as a percentage of all pituitary adenomas)

Pathophysiology
Lactotroph adenoma (prolactinoma) [6]
  • ∼ 40%
Somatroph adenoma
  • 10–15%
Corticotroph adenoma (Cushing disease)
  • ∼ 5%
Thyrotroph adenoma
  • ∼ 1%
Gonadotroph adenoma
  • Rare

Prolactinomas are the most common pituitary adenomas.

Clinical features

Type Secretory adenomas Non-secretory adenomas [5]
Microadenomas
  • Mostly asymptomatic
Macroadenomas

The symptoms associated with pituitary adenomas depend on the size of the tumor and whether the tumor produces hormones.

Diagnostics

Treatment

Following transsphenoidal resection and/or pituitary irradiation, patients may develop hypopituitarism and potentially require lifelong hormone replacement therapy.

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

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last updated 11/09/2020
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