A Case of Tuberculosis Misdiagnosed as Sarcoidosis and then Confirmed by NGS Testing

Pulmonary tuberculosis (PTB) is an important infectious disease that threatens the health and life of human beings. In the diagnosis of PTB, imaging plays a dominant role, but due to the increasing drug resistance of Mycobacterium tuberculosis, atypical clinical manifestations, "different images with the same disease" or "different diseases with the same image" in chest imaging, and the low positivity rate of routine sputum bacteriology, which leads to a high rate of misdiagnosis of PTB. We report a case of pulmonary tuberculosis that was misdiagnosed on imaging. We report a case of pulmonary tuberculosis that resembled sarcoidosis on imaging and was negative for antacid staining on sputum smear and alveolar lavage fluid, and was later diagnosed by microbial next-generation sequencing (NGS). The case was initially misdiagnosed as sarcoidosis.

Alveolar lavage fluid NGS, chest CT, bronchoscopy.

Chest CT showed multiple inflammatory lesions in both lungs, multiple nodular foci in both lungs, and multiple enlarged lymph nodes in the mediastinum and hilar region on both sides. Fiberoptic bronchoscopy was performed in the basal segment of the left lower lobe of the lungs to carry out bronchoalveolar lavage, and the lavage fluid was sent to the NGS test and returned the following results: Mycobacterium tuberculosis complex group detected in the number of sequences of 293. Based on the results of the NGS test, the diagnosis of pulmonary tuberculosis could be confirmed.

The diagnosis of pulmonary tuberculosis cannot be easily excluded in patients with "different images with the same disease" or "different diseases with the same image" on chest imaging without the support of sputum positivity. The goal was to improve the alertness of medical personnel to the misdiagnosis of tuberculosis and the application of NGS technology.