A benign neuroblastic tumor of the sympathetic nervous system that occurs in childhood. Ganglioneuroma typically arises from the sympathetic trunk in the mediastinum. Histologic features include spindle cell proliferation (resembling a neurofibroma) and the presence of large ganglion cells. Common presenting features include a palpable abdominal mass, hepatomegaly, and a thoracic mass detected on routine chest X-ray.