Prevalence:

• 1 in 6,000 births.

Ultrasound diagnosis:

• Multiple echogenic nodules in the heart (rabdomyoma, usually >20 weeks’ gestation) and brain (cortical tubers and subependymal nodules, usually >30 weeks’ gestation).
• Differential diagnosis: cardiac fibroma, which are single, large and often associated with pericardial effusion.
• Tuberous sclerosis is found in 50% of cases of rabdomyoma (in the other 50% of cases the cardiac tumor is an isolated finding). When there are multiple rabdomyomas the risk of tuberous sclerosis is >90%.

Associated abnormalities:

• Mutations in either the TSC1 or TSC2 gene, are found in 90% of cases.
• The tumors most often affect the brain, heart, skin, kidneys, eyes and lungs. However, prenatal diagnosis is confined to detection of the lesions in the heart and brain.

Investigations:

• Detailed ultrasound examination, including neurosonography.
• Search for the mutations in the TSC1 and  TSC2 genes.
• Fetal brain MRI may be useful if other brain abnormalities are suspected.

Follow up:

• Ultrasound scans every 4 weeks to monitor the evolution of cardiac tumors and development of arrhythmias and hydrops.

Delivery:

• Place: hospital with neonatal intensive care. 
• Time: 38 weeks, but ealier if there are arrhythmias or hydrops.
• Method: cesarean section if there is hydrops.

Prognosis:

• Arrhythmias, hydrops, and stillbirth in about 20% of cases.
• The cardiac tumors usually regress in early life, whereas the brain tumors usually increase in size and number.
• Prognosis depends on the number, size and location of the tumors.
• Wide spectrum ranging from normal life expectancy with mild symptoms to severe neurodevelopmental delay, epilepsy, autism and renal or pulmonary failure.

Recurrence:

• Autosomal dominant: 50% if one of the parents is affected.
• De novo mutations (65% of cases): no increased risk.