Atypical disseminated skeletal tuberculosis mimicking metastasis on PET-CT and MRI

Multifocal skeletal tuberculosis is a very rare manifestation of tuberculous infection. The multiple bone lesions of multifocal skeletal tuberculosis are difficult to differentiate from metastasis, even when performing 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (FDG PET/CT) or magnetic resonance imaging (MRI). A 25-year-old man presented with an abnormal chest X-ray. Radiologically, there were extensive osteolytic lesions on the skull, along the entire spine and on the ribs and both iliac bones, suggesting a diagnosis of bone metastasis. On FDG PET/CT, intensely increased F-18 FDG lesions were observed. A bone biopsy with a microbiologic study revealed a tuberculous infection. Follow-up PET/CT performed after treatment showed marked improvement in the extensive FDG uptake lesions.