A newborn child is noted to have a bulky abdominal tumor. CT scans reveal that the mass involves the right abdomen and retroperitoneum. The tumor is resected, revealing ganglion cells and primitive, small, round cells occasionally organized in rosettes, embedded in a fibrillary pink matrix. Special studies confirm the likely diagnosis. Which of the following features of this tumor is associated with a poorer prognosis?

Neuroblastoma is a childhood tumor of the sympathetic nerves, which most commonly arises along the paraveebral chain or within the adrenal medulla. Neuroblastoma has two characteristic genetic markers: a 1p deletion and an N-myc translocation. N-myc is an oncogene that resides on chromosome 2p, and is amplified up to 300 times in neuroblastoma. Amplification of this gene is associated with a poorer prognosis. Cellular aneuploidy and hyperdiploidy reflect a better prognosis for neuroblastoma, whereas diploid and tetraploid tumors have an intermediate or poor prognosis. Tumor presentation at a younger age predicts a better outcome for neuroblastoma.Children under one year of age have an excellent prognosis, regardless of tumor stage. Ganglion cells within the tumor are a reflection of focal differentiation of the neuroblastoma into ganglioneuroma. Better differentiated tumors have a more orable outcome. Ref: Graham D.K., Quinones R.R., Keating A.K., Maloney K., Foreman N.K., Giller R.H., Greffe B.S. (2012). Chapter 31. Neoplastic Disease. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.