Pituitary Adenomas
Pituitary adenomas are common intracranial neoplasms classified as microadenomas (<1 cm) or macroadenomas (≥1 cm). They are divided into functioning (hormone-secreting) and non-functioning tumors.
1. Functioning Adenomas (Common Types)
| Tumor Type | Clinical Presentation |
|---|---|
| Prolactinoma | Galactorrhea, amenorrhea (females); decreased libido, infertility (males). |
| Somatotropic | GH excess: Gigantism (children) or Acromegaly (adults). |
| Corticotropic | ACTH excess: Cushing’s disease (hypercortisolism). |
2. Local Mass Effects
- Bitemporal Hemianopsia: Compression of the optic chiasm.
- Hypopituitarism: Compression of normal pituitary tissue causes deficiencies in other axes (e.g., secondary hypothyroidism).
- Pituitary Apoplexy: Sudden hemorrhage into an adenoma; presents with acute “thunderclap” headache, visual field defects, and diplopia.
3. Exam Must-Knows
- Prolactinoma Treatment: First-line is medical management with dopamine agonists (cabergoline or bromocriptine).
- Acromegaly Testing: Elevated IGF-1 is the initial screening; failure to suppress GH following an oral glucose tolerance test is diagnostic.
Pathology Board Hint: For board exams, remember that prolactinoma is the most common functioning pituitary adenoma. If you see a patient with symptoms of hyperprolactinemia, always exclude pregnancy and hypothyroidism (TSH) before attributing it to a tumor.