Cardiac fibroma presenting as hypoplastic left heart syndrome in a foetus: causal or coincidental?

Primary cardiac tumours are very rare. Cardiac tumours in the perinatal period are even more uncommon with a prevalence of 0.0017% to 0.28% in autopsy series. The majority of benign cardiac tumours are cardiac rhabdomyomas, followed by cardiac fibromas. Another rare congenital heart disease is hypoplastic left heart syndrome (HLHS). Here we present a 21-week-old foetus diagnosed antenatally with HLHS on foetal echocardiogram. An autopsy done on the foetus following medical termination of pregnancy revealed a cardiac fibroma in the ventricular septum. It is very uncommon to have a combination of two congenital heart diseases. An extensive literature review revealed only three cases that had rhabdomyoma and associated HLHS. This case presented with cardiac fibroma which in early gestation would have resulted in left ventricular outflow obstruction leading to the development of HLHS. Small cardiac tumours which are difficult to detect by echocardiogram in early gestation can lead to the development of HLHS. A thorough and hierarchical autopsy examination of such cases can help in a better understanding of the relationship between HLHS and cardiac tumours.