Focal nodular hyperplasia in biliary atresia patient after Kasai hepatic portoenterostomy

We present the case of a 10-year-old girl with biliary atresia in whom focal nodular hyperplasia (FNH) of the liver occurred following successful "Kasai" hepatic portoenterostomy at the age of 2 months. Her jaundice completely disappeared a few weeks after the operation. A 4-cm diameter liver tumor in segment IV was found when she was 5-years old. Needle biopsy could not establish a definitive diagnosis. Because the tumor size was not changing, she was conservatively followed by abdominal echo at an outpatient clinic. She showed progressive liver dysfunction and ongoing cirrhosis, and so at the age of 10 years, she received living donor liver transplantation at our institute. The tumor was pathologically diagnosed as a FNH. Though a FNH in biliary atresia patients is extremely rare, there are only two cases reported in the literature; it should be considered in the differential diagnosis for a hepatic nodule during a long follow-up course in patients with biliary atresia.