Cardiac Rhabdomyoma in an Adult With a Previous Presumptive Diagnosis of Septal Hypertrophy

An 18-year-old woman had been complaining of palpitations and had suffered several episodes of syncope. When the patient was 6 years of age, echocardiography had revealed a localized area of septal hypertrophy without left ventricular outflow tract obstruction, and she was diagnosed with hypertrophic cardiomyopathy. Because of her recent symptoms, she was referred for a number of neurological and cardiac investigations, including cardiovascular magnetic resonance imaging (CMR). On CMR, there was a localized mass in the interventricular septum that extended from the level of the aortic valve toward the midcavity for a distance of approximately 50 mm, measuring 30 mm at its maximum width. On steady-state free precession cine, it appeared to be homogeneous without any definite demarcation from surrounding myocardium (Figure, A and B, and Movies I through V), and there was limited systolic motion of that part of the septum. There was no evidence of left …