Focal Nodular Hyperplasia in a Pediatric Cancer Survivor

Background: Focal nodular hyperplasia (FNH) are benign hepatic nodules that rarely occur in the pediatric population. Although pathogenesis of FNH is not elucidated, alteration in hepatic blood flow by vascular injury associated with chemotherapy and radiation therapy is thought to play a role. Differential diagnosis of hepatic nodules in the general population is wide and encompasses benign and malignant conditions. Discovery of hepatic nodules at follow-up in patients treated for pediatric malignancy raises a diagnostic dilemma. Case Information: In this case report, we discuss a 21-year-old Caucasian male who presented in 2006 at the age of 8-years with neuropathic leg pain and was diagnosed with embryonal rhabdomyosarcoma of the pelvis. Patient underwent protocol-directed chemotherapy with vincristine, actinomycin D, and cyclophosphamide, and radiation therapy. He completed therapy one year later in 2007 and has remained in continuous complete remission. Follow-up radiological imaging performed from year 2007 through 2020 include 3 computed tomography (CT) scans, 5 abdominal ultrasounds (US), and 2 abdominal magnetic resonance imaging (MRI). The initial diagnosis of FNH was suspected in 2015 by abdominal US and confirmed by MRI. Subsequent MRI and US imaging remained stable and consistent with FNH. No biopsy has been done. Conclusions: The discovery of FNH in follow-up post treatment may pose a diagnostic dilemma in pediatric cancer survivors. A systematic approach to radiological imaging will reduce the exposure of pediatric cancer survivors to unnecessary radiation, adverse effects, and invasive diagnostics.