Congenital neuroblastoma is defined as neuroblastoma identified within a month of birth, and is divided into:
In most cases they present as stage 1, 2 or 4S (see neuroblastoma staging).
In 90% of cases, fetal neuroblastomas arise in the adrenal glands. They have been diagnosed as early as 19 weeks of gestation, but usually are seen in the third trimester (mean age of diagnosis 36 weeks) .
In almost all cases the tumor undergoes maturation and regression, and prognosis is excellent with many institutions recommending conservative management .
Similarly neonatal neuroblastomas have much better prognosis than those found in older children with 90% being cured. In contrast to fetal neuroblastoma the adrenal glands are the site of tumor origin in only 45% of cases, and in ~ 60% of cases, metastases are present at the time of diagnosis. These are most frequently to the liver, which may be massively enlarged resulting in respiratory impairment .