A 3 month old, asymptomatic infant with tuberous sclerosis and multiple intracardiac tumours that were diagnosed prenatally (panel A) underwent surgery for resection of a large tumour (1.3 × 0.8 × 0.7 cm) obstructing the right ventricular outflow tract (RVOT) (panel B). After birth the infant was followed expectantly given that the natural history of these tumours is often spontaneous regression. However, the peak gradient across the RVOT increased steadily from 40 mm Hg to 100 mm Hg, prompting surgery to relieve the obstruction and break the cycle of stenosis begets hypertrophy begets stenosis. The large size of the tumour necessitated a right ventriculotomy (panel C). Histology confirmed the diagnosis of rhabdomyoma (panel D). Recovery from surgery was uneventful. The RVOT remained patent with a residual gradient of 34 mm Hg as measured by echo Doppler.

(A) Fetal echocardiogram, four chamber view, demonstrating multiple rhabdomyomas in the left and right ventricles (arrows). (B) Transthoracic parasternal short axis view. There is a large rhabdomyoma (arrow) causing obstruction of the right ventricular outflow tract. The tumour is situated immediately proximal to the pulmonary valve. Additional tumours are seen proximally in the right ventricle. (C) Intraoperative photograph. The tumour (arrow) demonstrated in panel B is excised through a right ventriculotomy. (D) Histology confirming the diagnosis of rhabdomyoma. Haematoxylin & eosin staining.