Asymptomatic primary tuberculous pleurisy with intense 18-fluorodeoxyglucose uptake mimicking malignant mesothelioma

The pathogenesis of primary tuberculous pleurisy is a delayed-type hypersensitivity immunogenic reaction to a few mycobacterial antigens entering the pleural space rather than direct tissue destruction by mycobacterial proliferation. Although it has been shown that pulmonary tuberculosis induces 18-fluorodeoxyglucose (FDG) uptake in active lesions, little is known about the application of FDG positron emission/computed tomography (FDG PET/CT) to the management of primary tuberculous pleurisy. We report a case of asymptomatic primary tuberculous pleurisy presenting with diffuse nodular pleural thickening without distinct pleural effusion and parenchymal lung lesions mimicking malignant mesothelioma. An initial FDG PET/CT scan demonstrated multiple lesions of intense FDG uptake in the right pleura and thoracoscopic biopsy of pleural tissue revealed caseous granulomatous inflammation. The patient received antituberculous therapy for 6 months, with clearly decreased positive signals on a repeated FDG PET/CT scan. FDG PET/CT imaging may be useful for evaluating disease activity in tuberculous pleurisy patients with an unknown time of onset.