Focal nodular hyperplasia (FNH) is a benign hepatic lesion very rarely described in the pediatric population. It has been reported more frequently in patients treated for pediatric cancers with chemotherapy or hematopoietic stem cell transplantation. The use of high dosage of alkylating agents, the occurrence of venous occlusive disease, graft-versus-host disease, and other variables linked to the hematopoietic stem cell transplantation procedure can represent risk factors for the development of FNH in the pediatric age. The discovery of hepatic nodules in the follow-up of patients treated for malignancies suggests recurrence of disease and raises a diagnostic dilemma. Here we describe possible risk factors, clinical and radiological findings of eight pediatric patients who developed focal nodular hyperplasia after hematopoietic stem cell transplantation. The aim of this report is to provide useful diagnostic tools to facilitate accurate diagnosis of FNH and suggest a correct management of this benign lesion during postcancer follow-up.