A 90-year-old woman with mild diabetes and Alzheimer disease dies in her sleep. At autopsy, hepatocytes are noted to contain golden cytoplasmic granules that do not stain with Prussian blue. Which of the following best accounts for pigment accumulation in the liver of this patient?

Advanced age. Substances that cannot be metabolized accumulate in cells. Examples include (1) endogenous substrates that are not processed because a key enzyme is missing (lysosomal storage diseases), (2) insoluble endogenous pigments (lipofuscin and melanin), and (3) exogenous particulates (silica and carbon). Lipofuscin is a "wear and tear" pigment of aging that accumulates in organs such as the brain, heart, and liver. None of the other choices are associated with lipofuscin accumulation.Diagnosis: Aging, lipofuscin