Case presentation
A 3‐month‐old female infant presented to our hospital with one month history of dyspnea.Transthoracic echocardiography demonstrated a large tumor mass(50mm×42mm) originated from the interventricular septum and filled the bilateral ventricular chambers(Figure 1). The patient underwent surgical resection of the tumor via the median sternotomy under cardiopulmonary bypass(CPB). During the operation, we found the tumor infiltrated the myocardium and the border between the tumor and the myocardium was unclear. Eventually we completely resected the tumor including part of myocardium. Interventricular septum was repaired with a bovine pericardium patch. The patient was weaned from the CPB and a postoperative transthoracic echocardiography confirmed no residual tumor and good ventricular function. Pathological examination revealed fibrosarcoma.
At one month follow up transthoracic echocardiography revealed a cystic dissection(43mmx32mm) located in the interventricular septum(Figure 2).This cystic dissection connected to the left ventricle through a 4.5mm defect,and to the right ventricle through several small holes of its thin walls(Figure 3,Movie S1).We defined this case as ventricular septal intramyocardial cystic dissection with residual shunts within the ventricular chambers due to the separation of myocardial layers and communication with ventricular chambers after operation. we performed conservative strategy, because of the high surgical risk, difficulty of interventional therapy and hemodynamic stability. At 9 months of follow-up, transthoracic echocardiography demonstrated the original cystic dissection was slightly reduced and the shunts between the cystic dissection and right ventricle disappeared. There was bidirectional shunt between the cystic dissection and left ventricle through the defect(Figure 4,Movie S2).The patient was asymptomatic and cardiac function was good. We continue to follow up the patient.