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.