Pituitary adenomas (also known as pituitary neuroendocrine tumors) are benign tumors that arise sporadically from the anterior pituitary gland. They are classified as either microadenomas or macroadenomas according to their size, and as either secretory (functional) or nonsecretory (nonfunctioning) according to their ability to secrete hormones. Secretory adenomas produce the pituitary hormone of the cell type from which they arise, which results in a state of hyperpituitarism. Nonsecretory macroadenomas can destroy the surrounding normal pituitary tissue, which results in hypopituitarism. Additionally, large macroadenomas compress the optic chiasm; therefore, patients may present with signs of mass effect such as bitemporal hemianopsia. MRI sella with IV contrast is the gold standard imaging method for the pituitary and should reveal any intrasellar masses. Pituitary hormone assays are used to evaluate patients for endocrine abnormalities, and perimetry is used to identify visual field defects. Transsphenoidal hypophysectomy is the first-line therapy for most patients with symptomatic pituitary adenomas; patients with nonsecretory microadenomas generally only require follow-up (until they become symptomatic), and prolactin-producing pituitary adenomas (prolactinomas) should be initially treated with dopamine agonists (e.g., cabergoline, bromocriptine). Pituitary irradiation is indicated in recurrent pituitary adenomas and/or if surgical therapy is contraindicated.