Microvesicular Steatosis

The patient is a 4 year-old boy on Valproate for seizures who developed elevated liver enzymes.

H&E shows microvesicular steatosis with scattered single cell hepatocellular necrosis. Microvesicular steatosis features a bubbly appearance and may be difficult to discern on light microscopy. Pure microvesicular steatosis is infrequent compared to macrovesicular steatosis. Recognition of the pure form is critical as it is often associated with serious liver diseases such as acute fatty liver of pregnancy, Reye’s syndrome, metabolic disorders (lysosomal acid lipase deficiency) and certain drugs (Valproate, total parenteral nutrition). Electron micrograph shows microvesicular steatosis (blue arrow) and giant mitochondria (black arrows). The latter may be encountered in drug-induced liver injury, fatty liver disease, and various metabolic disorders. The overall findings support Valporate-related liver injury.

Case provided by Kiyoko Oshima, MD, PhD, a pathologist and Director of Clinical Hepatic Pathology at Johns Hopkins University School of Medicine. The Survival Guide to Liver Biopsies that she and Dr. Lysandra Voltaggo wrote is now published by Innovative Science Press.

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