Autopsy of an 80-year-old man shows brown atrophy of the heart. Microscopy reveals granular yellow-brown pigment within cardiac myocytes that stains positive with Schmorl reaction and represents indigestible material from prior lipid peroxidation. This pigment is:
- A Melanin
- B Lipofuscin ✓
- C Hemosiderin
- D Bilirubin-derived cholestatic pigment
Explanation
Lipofuscin is an insoluble brown-yellow pigment composed of polymers of oxidized lipids and phospholipids complexed with protein, derived from free radical-catalyzed lipid peroxidation of subcellular membranes. It accumulates in lysosomes of slowly dividing cells such as cardiac myocytes and hepatocytes with age or atrophy, producing brown atrophy. Hemosiderin is golden-brown and iron-positive on Prussian blue stain. Melanin is produced by melanocytes and not a product of peroxidation. Cholestatic pigment is bile within canaliculi and hepatocytes, not intralysosomal granules.
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.