Diffuse cardiac lymphatic involvement by metastatic neuroendocrine carcinoma mimicking hypertrophic cardiomyopathy: a case report

We describe an autopsy case of non-functioning pancreatic neuroendocrine carcinoma metastasizing to the myocardium. A 63-year-old Japanese man was admitted to the hospital presenting with dyspnea. Echocardiography revealed marked left ventricular hypertrophy and diffuse myocardial thickening with pericardial effusion. The patient died of heart failure. An autopsy revealed that the whole pancreas, weighing 400 g, was occupied by tumor cells with neuroendocrine differentiation. The heart, weighing 780 g, showed numerous metastatic nodules and diffuse myocardial thickening. Histopathologically, the tumor was diagnosed as non-functioning pancreatic neuroendocrine carcinoma. Immunohistochemical analysis for D2-40 disclosed severe lymphatic infiltration of tumor cells, characterized by diffuse thickening of the myocardium.