Pedunculated focal nodular hyperplasia in a healthy toddler

Focal nodular hyperplasia (FNH) is a benign hepatic tumor rarely seen in pediatric patients, with most cases reported in school-aged children with a history of malignancy, liver disease, chemotherapy, or hematopoietic stem cell therapy. Despite having advanced radiographic imaging, diagnosing FNH before surgical resection can be difficult. We report a rare case of pedunculated FNH presenting as a large abdominal mass palpated on physical exam in a healthy 3-year-old girl with no history of malignancy or underlying liver disease. Ultrasound, computed tomography, and magnetic resonance imaging (MRI) did not demonstrate the typical imaging characteristics of FNH, because the mass was pedunculated with a poorly visualized central scar. Because approximately 75% of all primary hepatic tumors in this age group are malignant, this report also discusses the importance of adding hepatobiliary phase imaging with MRI to avoid, if possible, the need for biopsy or surgical resection of a benign hepatic tumor.