During an autopsy of a 70-year-old man who died of cardiac failure, the pathologist notices that several organs show a pattern of atrophy where individual cells have shrunk and contain small, golden-brown cytoplasmic granules. The organ most prominently affected is the heart, giving it a small, dark brown appearance with prominent epicardial fat remaining. What is the PRIMARY component of these golden-brown granules?

• A Lipofuscin from peroxidized membrane phospholipids ✓
• B Hemosiderin from degraded hemoglobin
• C Melanin produced by cardiac myocytes
• D Bilirubin deposited during chronic jaundice

Explanation

Lipofuscin ("wear and tear" pigment) is an insoluble polymer of oxidized lipids and proteins generated by autophagy of damaged organelle membranes, and accumulates as golden-brown perinuclear granules in aging post-mitotic cells such as cardiac myocytes and hepatocytes. The condition described — brown atrophy of the heart — is the classic example. Hemosiderin is coarser, stains with Prussian blue, and indicates iron overload; melanin and bilirubin are not produced by myocytes.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.