Tuberculosis or sarcoidosis: Opposite ends of the same disease spectrum?

Tuberculosis and sarcoidosis are chronic systemic diseases that have similar pulmonary and extra-pulmonary manifestations. Multiple studies have found an epidemiological, molecular, and immunological link between the two. It has been suggested that mycobacterium tuberculosis could be a common pathophysiologic mechanism for tuberculosis and sarcoidosis, and that both clinical entities can trigger similar immunological response in patients. Due to this close association, together with possible coexistence in the same patient, the diagnosis of one disease from another may be difficult. In our paper, we suggest that tuberculosis and sarcoidosis are two ends of the same spectrum. Given the pathophysiological and clinical link between the two, we also propose a classification system for tuberculosis and sarcoidosis: Sarcoidosis (S); Sarcoid-Tuberculous (ST); Tuberculous Sarcoid (TS) and Tuberculosis (TB). More research and clinical trials should first be done to affirm the link between the two disease entities.