Myxoid leiomyosarcoma of the left atrium: A rare malignancy of the heart and its comparison with atrial myxoma

Primary rumours of the heart are rare. The majority of these tumours are be nign, with myxomas located in the left atrium being the most common form. A lmost all malignant rumours are sarcomas and occur preferentially in the ri ght side of the heart. An exception to this rule is leiomyosarcoma, a rare form of primary cardiac sarcoma that occurs predominantly in the left atri um, as does cardiac myxoma. The case of a 53-year-old woman who presented w ith symptoms of mitral valve stenosis and pulmonary hypertension is reporte d. Cardiac catheterization, angiography and echocardiography revealed a lef t atrial mass that was interpreted as atrial myxoma. At the time of operati on, the myxoid appearance of the tumour mass further supported this assumpt ion. The tumour, including a wide rim of atrial septum, was removed with ca utery. Histopathological examination unexpectedly showed that the tumour wa s not an atrial myxoma but rather a myxoid variant of a primary leiomyosarc oma. Immunohistochemistry and electron microscopy confirmed the diagnosis. Local radiotherapy was considered but deemed con traindicated in View of th e longstanding pulmonary hypertension. Two months after excision, a repeat echocardiogram indicated recurrence of tumour in the left atrium, and the p atient died a few days later. The preferential left atrial location and the frequently myxoid appearance of primary leiomyosarcomas of the heart make it particularly difficult to differentiate them preoperatively from atrial myxomas. The authors recommend resection of ail atrial myxoid rumours with a wide (at least 1 cm) margin, combined with intraoperative frozen section diagnosis, because complete surgical resection appears to correlate with pr olonged survival in the few reported cases of atrial leiomyosarcomas. In ca ses of incomplete initial resection or local recurrence in the absence of m etastatic disease, heart transplantation may be a valid option in appropria tely selected patients.