Elevated CK from immune checkpoint inhibitor- related hypophysitis: a case report.

Area of Science:

• Oncology
• Immunology
• Endocrinology

Background:

• Immune checkpoint inhibitors (ICIs) are crucial in treating advanced cancers like melanoma and lung cancer.
• ICIs, by blocking CTLA-4 and PD-1 pathways, enhance anti-tumour immunity but can lead to immune-related adverse events (irAEs).
• Inflammatory myositis is a serious irAE, presenting with muscle weakness and elevated creatine kinase (CK).

Purpose of the Study:

• To report a case of ICI-related hypophysitis presenting as myopathy.
• To emphasize the diagnostic challenge of differentiating ICI-induced hypophysitis-related myopathy from inflammatory myositis.
• To highlight the importance of considering diverse causes of hyperCKemia in patients receiving ICI therapy.

Main Methods:

• Case report presentation.
• Review of clinical presentation, laboratory findings, and diagnostic workup.
• Discussion of differential diagnoses for hyperCKemia in the context of ICI therapy.

Main Results:

• A patient on ICI therapy developed hyperCKemia and muscle weakness.
• The condition was initially misdiagnosed as inflammatory myositis.
• Subsequent investigation revealed hypophysitis as the underlying cause of the myopathy.

Conclusions:

• ICI-related hypophysitis can manifest as a myopathy that mimics inflammatory myositis.
• Elevated CK levels in patients on ICI therapy warrant a comprehensive evaluation to exclude endocrine causes.
• Broadening the differential diagnosis is essential for accurate and timely management of irAEs.