A 26-year-old woman presented to our hospital f or radiologically abnormal pleural lesions at a health check-up. She was asymptomatic with normal laboratory findings. A chest X-ray showed diffuse nodular pleural thickening in the right hemithorax (Fig. 1A). On computed tomography (CT), the extensive pleural thickening involved interlobar fissures and the diaphragmatic pleura, combined with multiple lymphadenopathies in the mediastinum and the anterior diaphragmatic area (Fig. 1B and 1C). These lesions had increased 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography-computed tomography (PET-CT) (Fig. 2A–2C), suggesting pleural malignancy such as mesothelioma. Chest magnetic resonance imaging (MRI) with enhancement revealed that the pleural lesions showed moderate enhancement after contrast infusion and diffusion restriction on diffusion-weighted images (Fig. 2D and 2E). For a definite diagnosis, video-assisted thoracoscopic pleural biopsy was done. The lesion had chronic granulomatous inflammation with multi-nucleated giant cells with a negative PCR result for Mycobacterium tuberculosis/ non-tuberculous mycobacterium and a few acid-fast bacilli in Ziehl-Neelsen stain. Finally, M. tuberculosis was cultured in bronchial specimens.