A 32-year-old man without underlying diseases presented to the emergency department with an abrupt onset of gait disturbances and a 4-week history of back pain. The patient was afebrile, and all laboratory findings were normal. Rapid plasma reagin test for syphilis was negative. Whole-spine magnetic resonance imaging revealed an abnormal signal intensity with contrast enhancement at levels T3-T5 and level L3 (Fig. 1), as well as in the right sacral alar portion and left second rib (not shown). However, chest computed tomography (CT) showed no abnormalities in the lung parenchyma, airways, pleura, or lymph nodes. Bone scan suggested bone metastases in the skull, left clavicle, left third rib, and T3-T5 and L3 vertebrae. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/CT showed intense FDG uptake in multiple bone lesions and portocaval areas, possibly bone metastases and metastatic lymphadenopathy (Fig. 2). Percutaneous transpedicular bone biopsies were performed in the T4 and L3 vertebral bodies. Histopathological findings revealed chronic granulomatous inflammation with necrosis; however, acid-fast bacilli staining and duplex real-time polymerase chain reaction for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria from fresh bone tissue were negative. On the fifteenth day after the biopsy, the mycobacterial culture from the bone specimens tested positive for M. tuberculosis complex.

M. tuberculosis primarily infects the lungs. However, extrapulmonary tuberculosis (TB) can develop in other organs, including the lymph nodes, liver, spleen, bones, joints, and the central nervous system. Skeletal TB most commonly affects the spine, hips, and knees as a result of the reactivation of hematogenous foci, contiguous disease, or lymphatic spread [1]. Multifocal skeletal TB involving two or more non-contiguous bones is extremely rare and can mimic bone metastases, particularly in the absence of pulmonary involvement. The presence of necrotic lymph nodes increases the likelihood of extrapulmonary TB [2].