Pulmonary tuberculosis presenting secondary organizing pneumonia with organized polypoid granulation tissue: case series and review of the literature

BACKGROUND Secondary organizing pneumonia (SOP) is difficult to distinguish from cryptogenic organizing pneumonia (COP) considering various clinical situations. SOP caused by Mycobacterium tuberculosis is rare; indeed, it has not been reported as a sequela of disseminated tuberculosis. METHODS From January 2016 to December 2018, we identified six cases of tuberculosis-associated SOP in which Mycobacterium tuberculosis was revealed by microbiological examination; one of the cases was miliary tuberculosis. RESULTS Of the six cases, 17% were positive for acid fast bacillus (AFB) stain, but 100% were positive for M. tuberculosis polymerase chain reaction (MTB PCR) and AFB culture. In all cases, transbronchial lung biopsy was performed and organizing pneumonia was confirmed pathologically. All survived after treatment with anti-tuberculosis therapy. CONCLUSIONS Pulmonary tuberculosis, which shows OP in lung biopsy, is diagnosed through MTB PCR and AFB culture, and the prognosis is thought to be good.