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

Abstract

BackgroundThe 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.Case presentationWe 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.ConclusionFDG PET/CT imaging may be useful for evaluating disease activity in tuberculous pleurisy patients with an unknown time of onset.

Advances in imaging of tuberculosis

“…When compared with the series by Goo et al [12] and Kim et al [13], SUV max values and %Delta SUV max in lung tuberculoma were found to be higher. 18 F-FDG SUV max values and %Delta SUV max values were not significantly different in benign and malignant lesions. These findings are in agreement with the data reported by Chen et al [15], who included a selected group of patients with an initial mean 18 F-FDG PET SUV of less than 2.5.…”

“…In extrapulmonary TB, 18 F-FDG PET detects more tuberculous lesions than CT, is of value in assessing response to tuberculostatic treatment, and helps in diagnosing spinal infection and identifying TB-related spondylitis. 6.59) compared with inactive tuberculoma.…”

“…A study by Kaneko et al [16 & ] evaluated the retention indices of tuberculous and nontuberculous lesions and found that these were high in both types of lesions with no statistically significant differences. A recent case series by Heysell et al [17 && ] suggested a role for quantitative 18 F-FDG PET in the diagnosis of active TB infection in which conventional methods are unavailable or unreliable.…”

“…Extrapulmonary TB may affect any organ and is an AIDS-defining condition indicative of stage 4 disease in adults [19,20]. 18 F-FDG PET studies done on TB patients have demonstrated that PET detects more tuberculous lesions, especially extrapulmonary, than CT. Despite recent advances, the diagnosis of extrapulmonary involvement remains problematic, as obtaining tissue or fluid for analysis from these sites is not always possible and is invasive.…”

“…The use of 18 F-FDG is essentially based on its detection of increased glucose metabolism, which in TB is mainly due to increased macrophage and neutrophil activity. 18 F-FDG PET is unfortunately limited by its well documented lack of specificity and inability to clearly distinguish granulomatous disease from malignant involvement based on standardized uptake values (SUV max ) [2][3][4].…”