Unmasking AL Cardiac Amyloidosis During Familial Cardiomyopathy Screening.

BACKGROUND: Amyloid light-chain (AL) amyloidosis is a life-threatening plasma cell disorder in which prognosis is largely determined by cardiac involvement. Early diagnosis remains uncommon. CASE SUMMARY: A 65-year-old asymptomatic man was referred for familial hypertrophic cardiomyopathy screening. Echocardiography showed severe left ventricular hypertrophy, and cardiac magnetic resonance revealed biventricular hypertrophy with normal extracellular volume, along with late gadolinium enhancement in the interventricular septum and both atria, raising suspicion for infiltrative cardiomyopathy. Bone scintigraphy showed no pathologic cardiac tracer uptake (Perugini grade 0). An abnormal κ/λ ratio prompted hematologic work-up, and endomyocardial biopsy confirmed AL cardiac amyloidosis. Treatment with daratumumab, cyclophosphamide, bortezomib, and dexamethasone was initiated. DISCUSSION: This case highlights the diagnostic value of multimodality imaging and systematic monoclonal protein screening in unexplained ventricular hypertrophy. TAKE-HOME MESSAGE: A high index of suspicion is required to avoid missing early AL cardiac amyloidosis, particularly in patients with unexplained ventricular hypertrophy.