Unusual localization of a primary pleomorphic malignant fibrous histiocytoma on the mitral valve: a case report and review of the literature

INTRODUCTION: It has been reported that cardiac malignant fibrous histiocytomas occur more frequently in the left side of the heart, especially in the left atrium, but rarely invade the mitral valve. We present a case with a giant malignant fibrous histiocytoma with an unusual localization involving almost the entire left atrium, mitral valve, and left superior pulmonary vein. CASE PRESENTATION: We describe the case of a 54-year-old woman from Kosovo admitted to our emergency department with dyspnea. A transthoracic echocardiography demonstrated a giant mass localized on her left atrium. Our patient underwent emergent total surgical removal of the mass. The mass extended between her left superior pulmonary vein, and extended to her left atrium and the posterior mitral valve leaflet. We formulated a surgical plan for total separation of the mass from the endocardium. Total removal was performed and her left side pulmonary veins were entirely freed from the mass. We then performed a mitral valve replacement. The differential diagnosis included other masses of the left atrium, including thrombi, vegetations, and cardiac tumors. Postsurgical histopathologic results showed a pleomorphic malignant fibrous histiocytoma. Six monthly follow-up cardiac and abdominal sonographic examinations revealed no tumor recidivism. CONCLUSION: We reviewed 90 cases with malignant fibrous histiocytoma reported in the literature. Our case was especially unusual because of the primary location in the mitral valve, the pleomorphic variant, and the dimensions and extension. Complete surgical resection is mandatory to ameliorate symptoms and to obtain histologic information.