[Right ventricular thrombus mimicking a tumor mass in a newborn with pulmonary atresia--an autopsy report].

Intracardiac masses in infancy are not common. Tumors, thrombi and vegetations of bacterial endocarditis are exceedingly rare in this age group. These masses are seldom diagnosed before the infant's death. Two-dimensional echocardiography is a noninvasive technique that can detect and differentiate intracardiac masses that occur in infants. It can serially detect changes in the size or location of the masses, thus guiding subsequent medical or surgical intervention. An 11-day-old male newborn had suffered from lip and finger nail cyanosis, and dyspnea since 2 days old. Physical examination revealed subcostal retractions and no heart murmur during admission but a grade II/VI systolic murmur with a sometime grade II/VI continuous murmur which could be heard at the left upper sternal border 3 days after admission. The liver was palpable 2 cm below the right costal margin. The electrocardiogram was normal. The chest X-ray showed a normal sized heart (CTR = 0.58) with decreased pulmonary vascularity. Arterial blood gases revealed hypoxemia (PO2 24.1 mmHg) and metabolic acidosis, even though the patient was receiving O2 at 50%. The two-dimensional echocardiogram from the parasternal long axis view showed an echo-dense tumor mass in the right ventricular cavity. At autopsy, a complex congenital heart disease was found. The pathologic findings were: patent ductus arteriosus (1.0 x 0.5 cm), fenestrated foramen ovale, unopening pulmonary valve with thrombus (0.3 x 0.2 cm), right ventricular hypoplasia and hypertrophy of the right ventricular wall (1 cm in thickness). A ball like, organized and calcified thrombus, measuring 2.0 x 1.3 x 1.0 cm was found in the right ventricular cavity.(ABSTRACT TRUNCATED AT 250 WORDS)