Lighting up the muscles: ¹⁸F-FDG PET/CT in rare disseminated tuberculous myositis

Tuberculous pyomyositis is a rare and often under-recognized extrapulmonary manifestation of tuberculosis, presenting with non-specific symptoms such as fever and abscess, that may delay diagnosis. We report a unique case of disseminated tuberculous pyomyositis in a 56-year-old male with underlying chronic inflammatory arthritis. The diagnosis was confirmed using CBNAAT, line probe assay (LPA), and histopathology. Currently MRI is the standard imaging modality in use for imaging pyomyositis. ¹⁸F-FDG PET/CT can play a crucial role in detecting widespread metabolically active lesions involving multiple skeletal muscle groups and lymph nodes, which are not fully appreciated on conventional imaging and prove to be a sensitive imaging modality in such cases. This imaging modality provided a comprehensive assessment of disease burden, helping to map the full extent of involvement and guide clinical management. Early identification and treatment are essential, especially in atypical or disseminated cases, to prevent further complications and improve patient outcomes. Here we present a rare case presentation of such extensive muscular involvement in tuberculosis, highlighting the diagnostic utility of PET/CT in extrapulmonary TB.