Patient age: The age at diagnosis has profound effect on survival. According to the U.S. Surveillance, Epidemiology, and End Results (SEER) Statistics, the 5-yr survival for ages younger than 1 yr., 1 to 4 yrs., 5 to 9 yrs., and 10 to 14 yrs. is 90%, 68%, 52%, and 66% respectively. Neuroblastomas in older children and adult patients pursue an indolent but relentlessly progressive course with a worse long-term prognosis, regardless of stage. Site of Primary Tumor: Better survival has been noted for extra-adrenal primary tumors. Tumor Histology: The degree of cellular differentiation and maturation has a significant impact on prognosis and risk group assignment. Undifferentiated and poorly differentiated tumors do worse than differentiating neuroblastomas (shown in this image). Differentiating neuroblastomas show abundant neuropil and more than 5% of tumor cells show differentiation towards ganglion cells.