Deficiencies in the serum protease inhibitor alpha1-antitrypsin (AAT) may present in neonates, adolescents, or adults. Children with homozygous AAT deficiency develop neonatal cholestasis, which may progress to cirrhosis with prominent ductular reaction and partial preservation of lobular architecture. Homozygous adults present with pulmonary emphysema or liver disease. The latter manifests with periportal or periseptal PASD+ intracytoplasmic globules and variable fibrosis. Both heterozygous and homozygous disease can result in chronic hepatitis, cirrhosis, large-cell dysplasia, and hepatocellular carcinoma.