Multimodality imaging of extensive caseous-calcific myocardial involvement mimicking a cardiac mass

A 73-year-old asymptomatic obese woman was referred for pre-operative cardiologic evaluation before elective knee arthroplasty. Transthoracic echocardiography revealed asymmetric left ventricular hypertrophy with preserved systolic function, posterior mitral annular calcification and a large non-mobile hyperechogenic mass within the interventricular septum. Cardiac magnetic resonance confirmed asymmetric septal hypertrophy and identified septal and posterior mitral annular lesions characterized by markedly reduced native T1 and T2 values, hypoperfusion on first-pass perfusion imaging, and peripheral late gadolinium enhancement surrounding a non-enhancing core, consistent with calcification and surrounding fibrosis. Cardiac computed tomography demonstrated severe calcific degeneration of the mitral annulus extending into the interventricular septum and adjacent myocardium. Secondary metabolic, inflammatory, ischemic and infectious causes of myocardial calcification were excluded. This case highlights an unusual presentation of caseous mitral annular degeneration with intramyocardial extension mimicking a cardiac mass.