May 2015 Case of the Month
45 year-old woman underwent bariatric surgery, and during the sleeve gastrectomy procedure a wedge biopsy of the liver was performed. What is your diagnosis?
No significant fibrosis or frank cirrhosis observed on low power examination. Focal mild steatosis is present.
Trichrome stain is negative for cirrhosis or significant portal fibrosis.
Hepatocytes display PAS positive cytoplasmic globules.
No significant fibrosis or frank cirrhosis observed on low power examination. Focal mild steatosis is present.
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May 2015 Case of the Month
Answer: Alpha-1 Antitrypsin Deficiency
The liver biopsy shows frequent PAS positive (diastase resistant) hyaline-like globules within the cytoplasm of hepatocytes. A follow-up immunohistochemical stain for alpha-1 antitrypsin positively stains the globular material, confirming the diagnosis of alpha-1 antitrypsin (A1AT)deficiency. A1AT protein is a serine protease inhibitor that functions to prevent the degredation of connective tissues (especially lung alveolar walls) by several proteolytic enzymes. A1AT deficiency is caused by homozygous inheritance of a mutation in the SERPINA1 gene (denoted Z allele), resulting in abnormal accumulation and sequestration of the protein within hepatocytes. Patients with A1AT deficiency are at risk of developing pulmonary emphysema and liver disease that may progress to cirrhosis. Additional laboratory workup may include checking serum levels of A1AT, phenotypic testing by isoelectric focusing gel electrophoresis, or genotypic testing by DNA sequencing.