Tumors

Pituitary adenomas (functioning and nonfunctioning), craniopharyngiomas, posterior pituitary tumors (ganglioneuroma, astrocytoma), hypothalamic tumors (astrocytoma, germinoma), tumors of the skull base/optic chiasm (meningioma, glioma), metastases (most frequently breast and lung cancer)

Cystic lesions

Rathke cleft, arachnoid, epidermoid cysts

Cranial trauma and iatrogenic

Surgery (most frequently transsphenoidal sellar lesion), severe head trauma/brain injury, pituitary/sellar irradiation

Vascular

Postpartum pituitary infarction (due to postpartum hemorrhage [Sheehan syndrome]), pituitary apoplexy (sudden hemorrhage into the pituitary gland), internal carotid artery aneurysm (compression), stroke (ischemic or subarachnoid hemorrhage)

Inflammatory and infiltrative lesions

Sarcoidosis, hemochromatosis, Langerhans cell histiocytosis, granulomatosis with polyangiitis (formerly Wegener’s disease), hypophysitis related to immune checkpoint inhibitors, autoimmune, granulomatous, xanthomatous, or IgG-4 related disease

Drug/medication related

Supraphysiologic corticosteroids, high-dose opiates 

Infections

Tuberculosis, syphilis, mycoses, pituitary abscess, encephalitis, meningitis

Congenital (rare)

Familial hypopituitarism with multiple hormone deficiencies (PROP1, HESX1, PIT1) or developmental abnormalities (pituitary hypoplasia or aplasia)

Isolated hormone deficiencies

– Defective gonadotropin-releasing hormone synthesis (causing hypogonadotropic hypogonadism) associated with hyposmia, functional disorders, and certain medications

– Isolated deficiency of ACTH, TSH, or prolactin (very rare)

– Transient ACTH deficiency possible in the setting of prolonged higher-than-physiological glucocorticoid replacement

a The most common causes of hypopituitarism are in boldface.