Infiltrative and Inflammatory Disorders of the Hypothalamus and Pituitary

Hypophysitis is a rare disorder that results in inflammation of the pituitary gland. This can lead to hormonal dysfunction, pituitary enlargement, and mass effect. Hypophysitis can be primary or secondary. Etiologies include autoimmune (lymphocytic, IgG4), granulomatous (sarcoid, Langerhans, idiopathic, Erdheim-Chester Disease, granulomatosis with polyangiitis), xanthomatous hypophysitis, necrotizing hypophysitis, infiltrative (iron overload, amyloidosis), and infectious (bacterial abscess, tuberculosis, syphilis, viral, and parasitic). Determining the cause of hypophysitis is challenging as clinical presentation and imaging findings can mimic other pituitary disorders. Diagnosis often relies on pathology, and histological criteria often overlap between hypophysitis subtypes. Determining an etiology is important; therapy selection (glucocorticoids, immunosuppressive agents, chemotherapy, antibiotics, and/or surgery), long-term monitoring, and determining need for hormone replacement should be considered.