A case of malignant lymphoma arising from the pericardium

A 63-year-old man was admitted to our hospital with a complaint of exertional dyspnea due to AV block.Pacemaker implantation was performed, but he developed heart failure six months later.On echocardiography and chest CT, a tumor was found surrounding heart and invasion to the large vessels was detected.A metastatic tumor was suspected, but no primary lesion was discovered.A test thoracotomy was performed for final diagnosis.At operation, a part of the tumor of the pericardium was resected.We examined frozen sections and imprint smears microscopically. Cytologically, there were scattered large and medium sized neoplastic cells with very irregular, sometimes cleaved, nuclei containing coarse nuclear chromatin.Histologically, the tumor cells were diffusely proliferative.Immunohistochemically, the tumor cells were positive for LCA and L 26, indicating a malignant lymphoma of B cell origin.Imprint cytology is thought to be useful for rapid diagnosis of cardiac lymphoma, because of the difficulty in diagnosing malignant lymphoma on frozen sections.Moreover, the histogenesis of primary cardiac lymphoma is discussed on the basis of descriptions in the literature.