Endocrine Abstracts

Inflammatory lesions of the pituitary gland are rarely encountered. Recently, the concept of IgG4-related systemic disease was proposed and several cases associated with infundibulo-hypophysitis were reported. We report 4 additional cases and review the cases in the literature. Case 1: 75-year-old female had diabetes insipidus due to infundibulo-neurohypophysitis for 25 years and chronic thyroiditis. She developed obstructive jaundice and surgery showed autoimmune pancreatitis. Case 2: 78-year-old female developed hyponatremia, headache and visual field defect. MRI showed thickened pituitary stalk and enlarged gland. Transsphenoidal surgery was performed to decompress and pathology showed marked inflammatory fibrosis. Chronic sialoadenitis and retroperitoneal fibrosis was diagnosed with elevated serum IgG4 levels. Case 3: 70-year-old male had sialoadenitis and diabetes insipidus with thickened pituitary stalk. He had chronic thyroiditis and hypogonadism. Serum IgG4 was elevated. He developed hydronephrosis caused by retroperitoneal fibrosis. Case 4: 72-year-old male had syncope, and MRI showed marked enlargement of stalk and pituitary gland. Surgery showed inflammatory pseudotumor with marked infiltration of IgG4-positive plasma cells. Serum IgG4 was elevated. Glucocorticoid therapy rapidly reduced pituitary mass. Fifteen cases (male 12, female 3, median age: 70 years) have been reported in the literature. Associated IgG4-related diseases included retroperitoneal fibrosis (7), pancreatitis (6) and Mikulicz disease/salivary gland (4). Pituitary pathology was investigated in 4 cases, demonstrating the inflammatory pseudotumor with fibrosis and infiltration of IgG4-positive plasma cells.

IgG4-related infundibulo-hypophysitis is a new member of hypophysitis. Determination of serum IgG4 and search for systemic IgG4-related lesions are mandatory to avoid invasive pituitary surgery.