Blood cyst of the pulmonary valve causing right ventricular outflow tract obstruction: A case report.

Blood cysts are rare cardiac tumors, often involve the atrioventricular valves. Blood cysts are usually small and tend to be clinically silent. Here, we report a case of blood cyst adhered to the junction of the pulmonary valve and the right ventricular outflow, causing severe outflow obstruction. This case was initially misdiagnosed as pulmonary valve stenosis by transthoracic echocardiography (TTE) and even underwent percutaneous balloon pulmonary valvuloplasty (PBPV). As the right ventricle-to-pulmonary artery peak gradient did not decrease after PBPV procedure, the boy underwent TTE again and the diagnosis was corrected as blood cyst. The cystic mass was successfully resected subsequently, and the boy recovered well.