Discussion
Cardiac sarcoma are rare malignant tumors that usually occurs in the 3rd and 4th decade of life with a male predisposition (sex ratio 2.5:1) (3). Primary intimal sarcoma of the heart is subtype of sarcoma that arises from subendothelial cells in the intima of great blood vessels. This tumor of mesenchymal origin rarely involves the heart and, when it occurs, the left atrium and the mitral valve are more often affected (1).
As other cardiac malignancies, they can cause valvular or inflow-outflow tract obstruction, thromboembolism, arrhythmias, or pericardial disorders or be totally asymptomatic and discovered incidentally (4).
In this report, the initial pathologic diagnosis of myxoma is questionable. The histopathological analysis showed the presence of a myxoid stroma, spindle and stellar cells, the absence of necrosis and of identifiable mitotic figures which is consistent with the diagnosis of myxoma. In fact, the main concern was about the presence of nuclear atypias, which is not a usual pattern in case of myxoma and which could point towards a malignant nature of the initial tumor. Indeed, since cardiac intimal sarcoma are infrequent, initial pathological and radiological features might be confused with those of other malignant or even benign cardiac tumors (5).
Another hypothesis to explain the initial diagnosis of cardiac myxoma is that the intimal sarcoma has arisen from residual myxoma cells in the interatrial septum. Some authors have reported the possibility of malignant transformation of cardiac myxoma (6,7).This notion is however questioned by others who suggest that the malignant nature of the recurrent tumor is not always well defined (8). In our report, the malignancy and the histologic subtype of the second tumor is well established as the pathologic diagnosis was confirmed by immunohistochemical analysis (MDM2 overexpression) and by the development of a histologically proven metastatic disease.
The complete surgical resection with achievement of tumor free margin is the mainstay of the treatment but almost 50% of the patients are not suitable for this kind of resection due to the localization of the tumor (2). Intimal cardiac sarcoma is a highly aggressive tumor with a mean survival ranging from 3 months to 1 year. The life expectancy is twice as long for patients with complete surgical resection compared to patients with no resection (9). Other treatment modalities include radiation therapy and chemotherapy. Adjuvant therapy is usually offered to patients with surgically resected cardiac intimal sarcoma as recommended for soft tissue sarcomas (10). Cardiac transplantation is rarely considered as a treatment option because of the aggressive character of the intimal sarcoma and the high probability of distant micrometastasis at the time of diagnosis (11). In our case, despite a satisfactory local control after the second surgery, patient quickly developed a systemic metastasis, confirming that the cardiac transplantation was not indicated.