Overlap of Sjögren's Syndrome and Immune-Mediated Necrotizing Myopathy With Interstitial Lung Disease: A Case Report

Immune-mediated necrotizing myopathy (IMNM), an inflammatory muscle disease, typically presents as severe muscle weakness due to immunologic mechanisms. Some cases also show cutaneous manifestations, interstitial lung disease, and sicca symptoms. In this report, we present a unique case of an elderly man with a history of mild and stable Sjögren's syndrome (SS) for over 10 years, who later developed interstitial lung disease and myositis, leading to a diagnosis of IMNM confirmed by the presence of anti-signal recognition particle antibodies. The coexistence of IMNM and SS is a rare occurrence, underscoring the need for our expertise and a comprehensive understanding of the unique characteristics of each disease for accurate diagnosis and effective treatment.