Endocrine Abstracts

Hypophysitis is a rare inflammatory condition of the pituitary gland. Its pathogenesis is poorly understood and new variants have been recently described. It can be primary (isolated inflammation of the gland, not related with medications, systemic inflammatory disorders, infections, or other diseases), or secondary (associated with systemic inflammatory processes (as sarcoidosis, Wegener’s granulomatosis, Crohn’s disease, Takayasu’s arteritis, Cogan’s syndrome), inflammatory cell proliferative disorders (Langerhans cell histiocytosis, Erdheim-Chester disease), infections (as tuberculosis, syphilis), tumour-associated inflammatory infiltrate (as in germinoma), immunotherapy (as medications targeting cytotoxic T-lymphocyte antigen-4 (CTLA-4) or programmed cell death 1 (PD-1)), rupture of sellar cysts (Rathke’s cleft cysts and craniopharyngiomas)). The histological subtypes are lymphocytic, granulomatous, xanthomatous, and plasmacytic (also termed IgG4-related hypophysitis which is often a manifestation of systemic disease). The inflammation may involve the anterior pituitary gland (adenohypophysitis), posterior gland and stalk (infundibulo-neurohypophystis), or entire gland (pan-hypophysitis). Patients with hypophysitis present with manifestations related to mass effect from the gland enlargement and hypothalamo-pituitary dysfunction. The severity of hormone deficiencies may be out of proportion to imaging findings. Radiological findings include homogenous enhancement of the pituitary, diffuse symmetric gland enlargement, midline stalk thickening, and absence of a posterior pituitary bright spot. The diagnosis is established by biopsy and pathological examination. There are no prospective controlled studies on the optimal management of hypophysitis and treatment remains controversial; potential options include surgery (if visual deterioration), glucocorticoids (at variable dosages and duration), immunosuppressive agents and radiotherapy. Spontaneous resolution of pituitary enlargement has been observed in a number of cases and improvement of pituitary hormone deficits may occur after the resolution of hypophysitis.