Navigating Diagnostic Dilemmas in Cardiology: A Rare Case Report of Tuberculosis Presenting as a Cardiac Abscess.

Cardiac tuberculosis (TB) is a rare but important extrapulmonary form of TB that often presents diagnostic challenges due to nonspecific symptoms and its ability to mimic other cardiac conditions. We report the case of a 45-year-old woman with end-stage renal disease secondary to granulomatosis with polyangiitis (GPA) who presented with fever and a seizure-like episode. Initial investigations identified a cardiac mass located in the mitral-aortic intervalvular fibrosa and a cavitary lung lesion. Although sputum PCR tests for Mycobacterium tuberculosis were negative, histopathological examination and PCR analysis of the surgically resected cardiac mass confirmed necrotizing granulomatous inflammation consistent with TB. This case highlights the difficulty of diagnosing cardiac TB, particularly in patients with overlapping conditions such as GPA, as the similar granulomatous histopathology can complicate differentiation. The initial false-negative PCR results further emphasize limitations in current diagnostic tests, especially in immunocompromised hosts or atypical presentations. Given the complex interplay between cardiac TB and GPA, a multidisciplinary approach is essential for accurate diagnosis and management, with early recognition and tissue sampling critical to improving patient outcomes.