Lymphocytic (Autoimmune) Hypophysitis



  • A rare autoimmune disease that occurs when the pituitary gland is infiltrated with lymphocytes and plasma cells, leading to impaired hormonal secretion
  • Patients present with varying degrees of pituitary hormonal impairment or enlargement.
  • Cause is usually unknown.
  • The most common form affects the anterior pituitary and causes hypopituitarism.
  • Less commonly affects the infundibulum or posterior pituitary, causing diabetes insipidus and hyperprolactinemia


  • Predominantly seen in women: female > male (5:1)
  • Strong association with pregnancy, most frequently occurring in the gestational or postpartum period, but cases outside of pregnancy are increasingly seen
  • Females tend to present at a younger age (35 years) than do males (45 years).


  • Annual incidence estimated at 1 case per 9 million
  • Increasingly becoming more recognized
  • Thought to be underestimated because of the following:
    • Frequency of case reports are increasing.
    • Undiagnosed cases due to indolent disease


  • Uncommon
  • Found in <1% of all surgical pituitary samples

Etiology and Pathophysiology

  • Most commonly caused by an autoimmune infiltration that includes an admixture of T and B lymphocytes with plasma cells
    • Causes extrasellar pituitary enlargement
    • CD8 T cells mediate the attack on pituitary cells.
    • Antipituitary antibodies are considered markers of the T-cell mediation and are detectable in serum.
    • It is unknown if antipituitary antibodies play a pathogenic role.
  • Can also be caused by an inflammatory process
    • Initially leads to symptoms consistent with a pituitary mass effect (similar to pituitary adenoma)
    • Followed by fibrosis and shrinkage, causing differing degrees of hypopituitarism
    • Extension of the inflammatory process into the posterior pituitary and up into the neurohypophysis leads to diabetes insipidus, which is more common in males.
    • With complete progression, panhypopituitarism occurs with an empty sella turcica.
  • Autoimmune
  • Inflammatory


  • Patients often have family history of autoimmunity.
  • HLA DR4 allele, HLA DR5 allele (DR4 > DR5)
  • Recent association found with HLA DQ8 and DR53 alleles as well
  • Can be associated with antibody to PIT1 (POU1F1)

Risk Factors

  • Female gender
  • Pregnancy
  • Pregnant type 1 diabetics are at even higher risk.
  • Personal or family history of autoimmune disease
  • May be associated with viral infections, particularly meningoencephalitis
  • CTLA-4 antibody cancer treatment (e.g., ipilimumab or tremelimumab)

General Prevention


Commonly Associated Conditions

  • Aseptic meningitis: unknown if simple association or causal
  • Other autoimmune polyendocrinopathies are the following:
    • Hashimoto thyroiditis; Graves disease is most common.
    • Addison disease, type 1 diabetes mellitus, central diabetes insipidus, chronic atrophic gastritis, polyglandular autoimmune disease type 1 and type 3, systemic lupus erythematosus, Sjögren syndrome, autoimmune hepatitis, pernicious anemia, and primary biliary cirrhosis

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