Pituitary Adenoma
A pituitary adenoma causes illness through hormone excess, local mass effect, or loss of normal pituitary function; urgent recognition of visual compromise, adrenal insufficiency and pituitary apoplexy matters more than the scan label alone.
Definition
A pituitary adenoma is a usually benign neoplasm of the anterior pituitary, classified by size as a microadenoma under 10 mm or macroadenoma at least 10 mm, and by whether it produces a clinically important hormone excess. It causes disease through hormone excess, local mass effect or loss of normal pituitary function.
First principles
Read the lesion through three mechanisms
A sellar adenoma may secrete a hormone, compress nearby structures, or replace normal pituitary tissue. A prolactinoma causes hyperprolactinaemia; a somatotroph adenoma causes acromegaly; a corticotroph adenoma causes Cushing disease. A non-functioning lesion may still cause headache, visual field loss or hypopituitarism. The same patient can have more than one mechanism.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.