Differences between immunotherapy-induced and primary hypophysitis-a multicenter retrospective study.

Area of Science:

• Endocrinology
• Immunology
• Oncology

Background:

• Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events, including hypophysitis.
• Distinguishing immunotherapy-induced hypophysitis (IIH) from primary hypophysitis (PH) is crucial for appropriate management.

Purpose of the Study:

• To compare the clinical characteristics of IIH and PH.
• To identify distinct features that differentiate IIH from PH.

Main Methods:

• Retrospective multicenter cohort study.
• Inclusion of 56 patients with IIH and 60 patients with PH.
• Comprehensive endocrine testing, clinical data collection (age, gender, symptoms, endocrine dysfunction, MRI findings, immunotherapeutic agents, autoimmune diseases).

Main Results:

• IIH predominantly affects males and leads to more impaired pituitary axes in males compared to PH.
• Central hypocortisolism is more frequent in IIH, while diabetes insipidus is considerably less frequent.
• Visual impairment and pituitary stalk thickening are less common in IIH; 20% of IIH patients are asymptomatic.
• Concomitant autoimmune diseases are more prevalent in PH before diagnosis and in IIH during follow-up.

Conclusions:

• IIH and PH exhibit similar clinical presentations.
• Diabetes insipidus is rare in IIH, whereas central hypocortisolism is a characteristic feature.
• Pre-existing autoimmunity does not appear to predict the development of IIH.