Abstract: Normal Serum IgG4 in Biopsy Proven IgG4 Related Hypophysitis: A Case Report.

Authors

Areeba Minhaj, Anna Sunny, Mina Al-Sammarraie, Maheera Farooqi, Seba Issa, Nour Alijriri Alhesan

Published in

South Dakota medicine : the journal of the South Dakota State Medical Association. Volume 79. Issue suppl 5. Pages s40.

Abstract

IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder that can affect multiple organ systems. Pituitary involvement, referred to as IgG4-related hypophysitis (IgG4-RH), is uncommon but is increasingly recognized as a cause of hypopituitarism and central diabetes insipidus.
A 61-year-old man with type 1 diabetes presented with headaches, fatigue, and decreased libido. Laboratory evaluation revealed hypogonadism, secondary hypothyroidism, and secondary adrenal insufficiency. Brain MRI demonstrated a 9×7 mm hypoenhancing pituitary lesion with suprasellar extension. The patient was initially treated conservatively with hormone replacement therapy for presumed pituitary apoplexy. Three years later he developed polyuria and polydipsia and was diagnosed with central diabetes insipidus requiring desmopressin. He also reported progressive visual changes with bitemporal visual field loss. Repeat MRI showed interval extension of the lesion into the infundibulum. Transsphenoidal resection revealed dense lymphoplasmacytic infiltration with approximately 40 IgG4-positive plasma cells per high-power field and an IgG4: IgG ratio of 30%, consistent with IgG4-related hypophysitis. Notably, serum IgG4 level was normal (29.4 mg/dL), a finding observed in 30% of patients with IgG4-RD. Systemic evaluation did not reveal pancreatic disease. Chest CT showed features suggestive of IgG4-related lung involvement, which occurs in up to 30% of IgG4 related disease cases. PET/CT did not identify additional sites of hypermetabolic disease.
IgG4-RH accounts for less than 5% of all hypophysitis cases. Panhypopituitarism is the most common presentation of IgG4-related hypophysitis. This case highlights a diagnostically challenging presentation of IgG4-related hypophysitis with normal serum IgG4 levels. Clinicians should maintain suspicion for IgG4-RD in patients with unexplained hypophysitis even when serum IgG4 is normal.

PMID:
42526010
Bibliographic data and abstract were imported from PubMed on 30 Jul 2026.

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