Neonatal intracranial teratomas. Two neonates with intracranial teratomas presented with cranial enlargements a few weeks after birth. Both cases underwent surgery: one died intraoperatively; the other is the longest known survivor, alive 7 years and 9 months after subtotal excision of a mature teratoma of the left sylvian fissure. Previous operations have been relatively few and nearly all have been unsuccessful. Size and favorable location may be the most important prognostic features regardless of the histologic classification as mature or immature. One of our cases demonstrates that even subtotal excision of a mature teratoma can result in long-term survival. 