Polymyalgia Rheumatica Mimicking Infection and Malignancy: A Diagnostic Challenge Ruled Out by PET-CT

Polymyalgia rheumatica (PMR) is an inflammatory disorder affecting older adults, typically presenting with pain and stiffness in the shoulder and pelvic girdle. The clinical features may overlap with infection or malignancy, often leading to delayed treatment and extensive, sometimes unnecessary, investigations. We present a case of an elderly patient with prolonged shoulder pain and elevated inflammatory markers who underwent a comprehensive evaluation. MRI of the shoulder and PET-CT were performed to exclude alternative diagnoses. The imaging findings, combined with the clinical presentation and a rapid response to corticosteroid therapy, confirmed the diagnosis of PMR. This case underscores the pivotal role of PET-CT in the diagnostic workup of atypical PMR, facilitating the exclusion of sinister pathologies such as malignancy or infection, guiding clinical decision-making, and reducing the need for unnecessary invasive investigations.