An 80-year-old man presents with progressive biventricular heart failure. Echocardiography shows thick ventricular walls with a sparkling texture and preserved ejection fraction. Endomyocardial biopsy shows amorphous eosinophilic deposits staining with Congo red. Mass spectrometry of the deposits identifies wild-type transthyretin. This form of amyloidosis is characterized by:

• A Hereditary amyloidosis requiring mutant transthyretin, invariably presenting before age 40
• B Reactive systemic amyloidosis from serum amyloid A produced in chronic inflammation
• C Senile systemic amyloidosis from deposition of normal transthyretin, mainly cardiac in elderly men ✓
• D Dialysis-associated amyloidosis from beta-2 microglobulin deposition in osteoarticular structures

Explanation

Deposition of structurally normal wild-type transthyretin defines senile systemic amyloidosis, seen predominantly in men over 70 years with restrictive or hypertrophic-like cardiomyopathy and atrial involvement. Option A is wrong because mutant TTR causes familial amyloid polyneuropathy and cardiomyopathy typically in mid-adulthood, not invariably under 40, and this patient's deposits were typed as wild-type. Beta-2 microglobulin amyloid targets joints and bone in long-term dialysis patients, not the myocardium.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.