A 78-year-old man dies of advanced esophageal cancer. The man's family donates his body for teaching purposes and an autopsy is performed. Gross examination of the heart reveals left ventricular chamber size and wall thickness within normal limits. No significant atherosclerosis is seen in the coronary arteries. On microscopic examination, myocardial cells demonstrate prominent yellow-brown intracytoplasmic granules as shown in the exhibit.
Which of the following most likely accounts for the observed microscopic changes?

Question

A 78-year-old man dies of advanced esophageal cancer.  The man's family donates his body for teaching purposes and an autopsy is performed.  Gross examination of the heart reveals left ventricular chamber size and wall thickness within normal limits.  No significant atherosclerosis is seen in the coronary arteries.  On microscopic examination, myocardial cells demonstrate prominent yellow-brown intracytoplasmic granules as shown in the exhibit.
  Which of the following most likely accounts for the observed microscopic changes?

Quizplus · Accepted Answer

The yellow-brown pigment contained within intracytoplasmic granules (ie, residual bodies) in this man's myocardium represents lipofuscin. Lipofuscin is composed of lysosomal breakdown products including lipid polymers and protein-complex phospholipids that result from free radical injury and lipid peroxidation. The insoluble granules are considered a wear-and-tear product that accumulates with age, and they are commonly seen in low-turnover cells (eg, heart, liver, central nervous system) of the elderly. Malnourishment, as may have been present in this man with advanced esophageal cancer, may contribute to increased lipofuscin production. (Choice A) A common example of exogenous pigment endocytosis occurs when urban-residing individuals inhale carbon or coal dust that is taken up by macrophages within the lung parenchyma, resulting in prominent black pigment (ie, anthracosis). (Choice B) Glycogen is a glucose polymerization product and typically appears as clear vacuoles within the cytoplasm. These clear vacuoles are seen in abundance in patients with glycogen storage disease. (Choice C) Iron-containing brown pigment called hemosiderin is often seen in areas of localized iron overload caused by bleeding into tissues. Decompensated heart failure causes leakage of edema and erythrocytes into the lung parenchyma, and hemosiderin-laden macrophages can be seen. (Choice E) Hyaline is a form of protein accumulation that can be intracellular or extracellular. It typically appears as a glassy, homogeneous pink deposit, as seen with hyaline arteriosclerosis of the kidney. (Choice F) Melanin is an oxidation product of tyrosine metabolism and typically appears as pigmented granules dark brown to black in color. Melanoma demonstrates high melanin content. Educational objective: Lipofuscin is a yellow-brown pigment composed of lysosomal breakdown products of lipid polymers and protein-complex phospholipids. It is considered a wear-and-tear product and marker of aging because it accumulates over time, and residual bodies containing lipofuscin are prevalent in low-turnover cells (eg, heart, liver, central nervous system) of the elderly. __________ References: Myocardial lipofuscin accumulation in aging and sudden cardiac death. (http://www.ncbi.nlm.nih.gov/pubmed/30824797)

A 78-Year-Old Man Dies of Advanced Esophageal Cancer