Descending Necrotizing Mediastinitis Initially Misinterpreted as a Musculoskeletal Disorder: A Case Report

Descending necrotizing mediastinitis (DNM) is a rare but life-threatening infection in which early diagnosis is critical, although atypical symptoms and subtle initial imaging findings may delay recognition. We report a 57-year-old man with diabetes mellitus who presented with fever and severe right posterior neck pain radiating to the shoulder, initially leading to orthopedic evaluation; the pain was disproportionately severe relative to physical findings and refractory to analgesics, with retrosternal tenderness. Laboratory tests showed elevated C-reactive protein with mild leukocytosis, thrombocytopenia, hypoalbuminemia, and coagulopathy, while initial noncontrast CT showed subtle findings, including pleural effusion and increased retrosternal soft tissue density. Contrast-enhanced CT the following day revealed a mediastinal abscess, and blood cultures yielded methicillin-susceptible Staphylococcus aureus; the patient improved with antimicrobial therapy without surgical drainage. This case highlights that unexplained severe pain disproportionate to physical findings should prompt consideration of deep-seated infection and timely contrast-enhanced imaging when DNM is suspected.