Sarcoidosis: Rare manifestations and diagnostic dilemma in tuberculosis endemic regions: review of literature with case studies

Sarcoidosis is a systemic inflammatory disorder of unknown etiology, characterized by the presence of non-caseating epithelioid cell granulomas. Growing literature on sarcoidosis in India has led to an increased awareness of the disease. With the advent of better diagnostic tools, rare manifestations of sarcoidosis are likely to be recognized. However, a lot of diagnostic dilemma is associated with sarcoidosis. Clinical, radiological and histopathological similarities with tuberculosis pose even a greater diagnostic challenge in countries endemic to tuberculosis. Not only sarcoidosis is a close mimic of TB, but TB has been linked to the causation of sarcoidosis. Recent advances in immunologic and molecular techniques have strengthened the association between mycobacteria and sarcoidosis. Aims & Objectives: (1) To study the rare manifestations in patients with sarcoidosis. (2) To demonstrate the sarcoidosis-tuberculosis link, diagnostic modalities and dilemma in the diagnosis. Method: Retrospective review of records of 20 patients with histopathologically proven sarcoidosis seen over 2 years in a tertiary care centre in Kanpur, was done. Results: 20% (4 out of 20) cases had rare manifestations (one had isolated bone marrow sarcoidosis, two had isolated liver involvement and the fourth case had uterine sarcoidosis) while the rest 80% had lung or/and lymph node involvement. 6 (30%) out of 20 cases had a tuberculosis link. Four had tuberculosis and then later developed sarcoidosis, one had sarcoidosis and then later developed overt tuberculosis; one had coexisting tuberculosis and sarcoidosis. Conclusion: The clinicians and pathologists should keep in mind the rare sites of sarcoidosis before making a diagnosis of tuberculosis in India and should further investigate the patients for sarcoidosis. Also, in patients having recurrent tuberculosis or not responding to ATT with granulomatous pathology, a diagnosis of sarcoidosis should be thought of.