Which is the commonest abdominal mass in neonate :

The commonest intra - abdominal tumor in first two years of life → Neuroblastoma. The commonest intra - abdominal tumor between 2nd to 5th  year of life → Wilm’s tumor. The commonest intro - abdominal tumor in children (no age specification) → Neuroblastoma. (Wilm's tumor is the second most common abdominal tumor in children). Remember: The commonest cause of abdominal mass in Newborn is Multiple dysplastic kidneys (if neoplasm or tumor has not been mentioned when asking for the commonest intra-abdominal mass, the answer will be multiple dysplastic kidneys).