What is focal nodular hyperplasia?

DEFINITION A benign hepatic tumor thought to arise from hepatocytes and bile ducts that has a characteristic “central scar” on pathologic evaluation. INCIDENCE Most common in premenopausal females. SIGNS AND SYMPTOMS Usually asymptomatic; 10% of patients present with abdominal pain and/or a RUQ mass. DIAGNOSIS Usually incidental on ultrasound or CT; can be differentiated from hepatocellular adenoma by a Tc-99 study. Biopsy/US or CT TREATMENT Resect if patient is symptomatic.