Tuberculosis presenting as metastatic lung cancer

Mycobacterium tuberculosis infection (TB) masquerading as lung tumor is well reported, but its mimicry as metastatic thoracic cancer is rare. We report the case of a young male who presented with clinical and radiological picture of lung cancer but investigations confirmed it as TB. A 35-year-old male, with 18-pack year of smoking history, presented with dry cough, anorexia, weight loss, and lower back and left hip pain. Chest imaging showed right upper lobe speculated mass with mediastinal and hilar lymphadenopathy and a lytic lesion in the left sacral area. Magnetic resonance imaging of the spine and pelvis revealed lytic lesion in the left sacrum. Fluorodeoxyglucose positron emission tomography computed tomography scan of the whole body showed hypermetabolic lung lesion with ipsilateral mediastinal, supraclavicular, splenic, and bone metastasis in the left aspect of the sacrum. Computed tomography (CT)-guided biopsy of the lung lesion showed necrotizing granuloma and tissue culture was positive for pan-susceptible M. tuberculosis. Follow-up CT scan showed complete resolution of the lung lesion and lymph nodes after anti-TB treatment with significant reduction in the sacral lesion. Mycobacterial infection may mimic metastatic lung cancer and should always be considered a differential diagnosis