Acute fatty liver of pregnancy results from a defect in mitochondrial fatty acid oxidation and presents with hepatic dysfunction. This condition occurs in 1/15,000 pregnancies and 20% have coexisting pre-eclampsia. It is usually mild but may progress to hepatic failure and death. The only treatment is termination of the pregnancy. Histologic features include microvesicular steatosis in zones 2 and 3 and ballooning hepatocyte degeneration. Severe cases show loss of hepatocytes, collapse of the reticulin framework, and portal inflammation.