Diffuse Infiltration of Lymphoma of the Myocardium Mimicking Clinical Hypertrophic Cardiomyopathy

A 51-year-old man with good health previously presented with a 1-month history of shortness of breath on exertion. Transthoracic echocardiography revealed marked biventricular hypertrophy, mild mitral regurgitation, and moderate tricuspid regurgitation, suggestive of hypertrophic cardiomyopathy (Figure 1A and 1B; Movie I and Movie II). In the parasternal short-axis view, thickening of the left atrial wall and para-aortic tissue were evident, which is unusual in typical hypertrophic cardiomyopathy, a disease that primarily affects the ventricular myocardium (Figure 1C and Movie III). Computerized tomographic arteriography revealed no coronary artery disease. His heart failure symptoms worsened, and atrial fibrillation developed. At the same time, maculopapular skin rash developed on the upper trunk and the head and neck region. Hypercalcemia with an adjusted serum calcium level greater than 4 mmol/L was recorded. Other blood chemistry and hematologic examinations were unremarkable. His conditions deteriorated rapidly and, despite maximal supportive measures, he died 1 week after hospitalization. Limited clinical postmortem examination revealed a well-built gentleman with a heart weighing 790 g (Figure 2A). The walls of all 4 chambers of the heart were diffusely thickened by tan-colored infiltrative growth. The left and right ventricular …