Dilemma of diagnosing thoracic sarcoidosis in tuberculosis endemic regions: An imaging-based approach. Part 1

Sarcoidosis is a multi-systemic disorder of unknown etiology, although commonly believed to be immune-mediated. Histologically, it is characterized by noncaseating granuloma which contrasts against the caseating granuloma seen in tuberculosis (TB), an infectious disease that closely mimics sarcoidosis, both clinically as well as radiologically. In TB-endemic regions, the overlapping clinico-radiological manifestations create significant diagnostic dilemma, especially since the management options are markedly different in the two entities. Part 1 of this review aims to summarize the clinical, laboratory, and imaging features of sarcoidosis, encompassing both typical and atypical manifestations, in an attempt to distinguish between the two disease entities.