A 45-year-old man with early-onset emphysema and elevated liver enzymes undergoes a liver biopsy. The hepatocytes show cytoplasmic globules that are periodic acid-Schiff (PAS) positive and diastase resistant. Which intracellular accumulation is responsible for these findings?
- A Accumulation of copper in lysosomes
- B Accumulation of alpha-1 antitrypsin in the endoplasmic reticulum ✓
- C Accumulation of lipofuscin in the cytoplasm
- D Accumulation of glycogen in the nucleus
Correct answer: B. Accumulation of alpha-1 antitrypsin in the endoplasmic reticulum
Explanation
In alpha-1 antitrypsin deficiency, the Z mutation causes polymerization of the protein in the endoplasmic reticulum of hepatocytes. These retained polymers form PAS-positive, diastase-resistant globules. Copper accumulation occurs in Wilson disease and stains with rhodamine or orcein. Lipofuscin is a wear-and-tear pigment, and nuclear glycogen is seen in diabetes, but neither forms the characteristic PAS-positive globules of B1AT deficiency.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
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