Malignant benign neonatal sacrococcygeal teratoma.

Thirty-six patients with benign neonatal sacrococcygeal teratoma (SCT) were treated in our medical center from 1972 to 1990. Mean gestational age was 38.6 +/- 3.3 weeks with a mean birth weight of 3,484.0 +/- 938.5 g. Twenty-nine patients (89%) were females. The majority of the tumors (75%) contained cystic components and 96% were Altman classification I and II. The initial surgical removal of the SCT (including the coccyx) was carried out during the first 7 days of life. Six patients (22%) developed recurrence of the tumor. Three were benign and reappeared locally after 12 +/- 3 months and were reexcised. The mean serum alpha-fetoprotein level in this group was 13 +/- 1 g/L. The malignant recurrence (all originally reported as being mature benign SCT) appeared at 20.3 +/- 1.5 months and had markedly elevated serum alpha-fetoprotein levels (7,320 +/- 4,630 micrograms/L). All the patients in this group had multimodal therapy including complete excision of the recurrent tumor. We conclude that SCT, although histologically benign, has an alarming potential to recur either as a benign or malignant tumor during the first 2 years of life. Close follow-up for at least 3 years (frequent examination, serum alpha-fetoprotein, and diagnostic imaging) is recommended for all patients who had undergone excision of SCT in the newborn period.