Cytomegalovirus endomyocarditis in a transplanted heart. A case report with in situ hybridization.

A 64-year-old man underwent cardiac transplantation for long-standing severe dilated cardiomyopathy. Postoperative complications included primary cytomegalovirus (CMV) infection with several episodes of moderate acute rejection and severe pneumonia. Six months after transplantation, an endomyocardial biopsy specimen revealed focal necrotizing myocarditis with intranuclear inclusions consistent with CMV. The patient subsequently developed fulminant pneumonia and died 7 months after transplantation. Postmortem examination revealed that the cause of death was acute necrotizing bronchopneumonia due to Staphylococcus aureus, with underlying CMV pneumonitis. The transplanted heart had left ventricular hypertrophy with multiple organizing myocardial infarcts, moderate coronary atherosclerosis, and organizing thrombi of the left atrium. Characteristic inclusions of CMV were identified, predominantly within endothelial cells, in the left coronary artery, left ventricular endocardium, and myocardium. With in situ hybridization, the presence of CMV was verified in the inclusions, as well as in many fibroblasts without inclusions. In situ hybridization is warranted in myocardial biopsy specimens when suspicious inclusions or infiltrates are present, to confirm CMV infection, so that appropriate therapy can be initiated.