Herein we present a case of fulminant myocarditis in a woman previously treated for B-cell lymphoma. While the clinical context was suggestive of adriamycin-induced cardiomyopathy, the initial pathology of the Heartmate-2 apical core showed lymphocytic myocarditis. After 8 months of stability, the patient presented with progressive heart failure and recurrent ventricular arrhythmias. An endomyocardial biopsy revealed findings typical of giant cell myocarditis (GCM); poor response to immunosuppressive therapy and marked hemodynamic instability led to urgent transplantation. To our knowledge, this is the first reported case of GCM following an acute lymphocytic myocarditis and the second GCM case associated with B-cell lymphoma.