Ganglioneuroblastoma, light micrograph. Ganglioneuroblastomas are intermediate tumours arising from nerve tissue. An intermediate tumour is one that is between benign (slow-growing and unlikely to spread) and malignant (fast-growing, aggressive, and likely to spread). This is a rare childhood cancer that has a yearly occurrence of less than 5 in 1,000,000 children. A ganglioneuroblastoma may be localised to one area or it may be widespread, but it is usually less aggressive than a neuroblastoma. The cause is unknown.