From Giant Cells to Granulomas: A Diagnostic Odyssey in Inflammatory Cardiomyopathy

Giant cell myocarditis (GCM) and cardiac sarcoidosis (CS) are rare, inflammatory cardiomyopathies with overlapping presentations but differing treatments and prognoses. We present a case of a middle-aged woman diagnosed initially with GCM based on clinical presentation and endomyocardial biopsy. After unexpected clinical improvement and persistent mediastinal lymphadenopathy, lymph node biopsy revealed non-necrotizing granulomas, leading to a revised diagnosis of CS. This case highlights the diagnostic challenges presented by inflammatory cardiomyopathies and the importance of reassessing initial diagnoses in the context of evolving clinical and imaging findings.