At autopsy of an 82-year-old man with chronic heart failure, the myocardium is dark brown. Histology shows fine, yellow-brown, granular perinuclear pigment within cardiomyocytes. Electron microscopy reveals this pigment within lysosomes. What is the nature and significance of this pigment?

• A Melanin derived from neural crest cells, indicating metastatic melanoma
• B Lipofuscin, an insoluble product of lipid peroxidation accumulating in lysosomes with aging ✓
• C Hemosiderin from prior hemorrhage, confirming iron overload cardiomyopathy
• D Ceroid pigment pathognomonic of Niemann-Pick disease

Explanation

Lipofuscin, also called wear-and-tear or aging pigment, is an insoluble brownish-yellow granular intracytoplasmic material composed of polymers of lipids and phospholipids complexed with protein. It arises from free radical-catalyzed peroxidation of polyunsaturated lipids of subcellular membranes and is indigestible, so it persists in lysosomes. It accumulates progressively with age in heart, liver, and neurons, producing brown atrophy of organs. Prussian blue negativity distinguishes it from hemosiderin (option C).

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.