The incidence of suprarenal tumours/masses has increased in the last decade due to the expanded use of prenatal ultrasonography in routine obstetric care and in the neonatal and early infancy care. The differential diagnosis of these masses ranges from benign (adrenal haemorrhage) to malignant processes (neuroblastoma, adrenal carcinoma). Knowledge on perinatal suprarenal masses, although based on a relatively large literature, is scattered amongst studies on very few cases with no methodical approach and often short follow up. Therefore, the optimal management of these masses has not been clearly defined. Neuroblastoma at this age is an intriguing entity with a very good prognosis in most cases. The SIOPEN Group, based on their results in the first multicenter European Trial for infants with neuroblastoma (INES) and the world-wide experience provided in the literature, is launching this European surveillance study (Multi-centre, non-blinded, one armed prospective trial) for these masses. Treatment: Observation