Granulomatous Myocarditis as Rare Presentation of Mycobacterium tuberculosis: A Series of Four Autopsy Cases

Tuberculosis (TB) is a communicable disease caused by the organism Mycobacterium tuberculosis. It has been a leading cause of mortality and a global public health emergency for the last 25 years. Despite being a predominantly pulmonary infection, Mycobacterium tuberculosis can affect other organs, such as the nervous system, gastrointestinal system and, rarely, the cardiovascular system. This infection can sometimes present as Tuberculous Myocarditis (TM) in the cardiovascular system, an extremely unusual presentation that can be difficult to diagnose, especially in areas where TB is endemic, like India. Authors report four cases of Granulomatous Myocarditis (GM) across a wide range of age groups, who presented with non specific symptoms of giddiness followed by sudden unconsciousness and death. On gross examination of the hearts received after autopsy, two cases showed left ventricular focal white lesions, while one additionally showed Left Ventricular Hypertrophy (LVH). The hearts in the other two cases were grossly unremarkable. Microscopic examination of the cardiac tissue revealed multiple caseating granulomas composed of necrosis, epithelioid cells and lymphocytes. Three out of four cases also showed disseminated TB. Based on the histopathological examination of the granulomas, Mycobacterium tuberculosis aetiology was suspected in all cases. Herein, present series describe the pathological characteristics of this most unusual variant of Mycobacterium tuberculosis.