Large left ventricular apical aneurysm in a child with Noonan syndrome and hypertrophic cardiomyopathy.

Noonan syndrome (NS) is a multisystem disorder with frequent heart defects, including hypertrophic cardiomyopathy (HCM). Left ventricular (LV) apical aneurysm is an extremely rare presentation in pediatric HCM. A 4-year-old child with NS, PTPN-11 mutation and HCM presented with progressive mid-cavity LV obstruction leading to a large LV apical aneurysm. Magnetic resonance imaging confirmed a large, wide-neck LV apical aneurysm. Surgery combined septal myectomy and patch repair of the aneurysm, resulting in uneventful recovery and significant gradient reduction. While multimodal imaging assists surgical planning, longitudinal surveillance should look for recurrences of aneurysm from the repaired segment, arrhythmia, and myocardial function.