Immunoglobulin G4 hypophysitis in a 63-year-old woman with no autoimmune history: a case report.

BACKGROUND: Immunoglobulin-G4-related hypophysitis is a rare inflammatory disease that can present as a tumefactive pituitary lesion mimicking hypophyseal neoplasms such as pituitary adenoma or craniopharyngioma. The literature on this entity is sparse, with fewer than 100 cases reported across 19 publications; a recent review found only 24 cases published from 2007 to 2018. Previous reports have described demographic differences, with immunoglobulin-G4-related hypophysitis in females tending to present in the second and third decades in association with other autoimmune disease, while males tend to present in the fifth and sixth decades of life without an autoimmune history. CASE PRESENTATION: In contrast to the reported demographic trends, here we describe a unique case of immunoglobulin-G4-related hypophysitis in a 63-year-old white female with no history of autoimmune disease who presented with a rapidly enlarging sellar and hypothalamic mass causing headaches and cranial nerve palsies, prompting biopsy for diagnosis. The patient experienced rapid response to treatment with high-dose steroids and rituximab. CONCLUSION: The case contributes to the growing clinicopathologic description of immunoglobulin-G4-related hypophysitis and illustrates that this diagnosis should be a consideration even outside the conventional demographic setting.