[Retroperitoneal teratomas in the perinatal period. Review of the literature concerning a neonatal, immature, aggressive teratoma].

A neonate with an immature, poorly demarcated retroperitoneal teratoma invading the aorta-vena cava space died immediately after surgery. Among 34 cases of retroperitoneal teratoma discovered during the first postnatal month, including one renal case and ours, eight can be considered malignant on the basis of histology in two cases and clinical course in six. Five of these tumors exhibited a significant immature component. In neonates, the proportion of malignant teratomas is greater for retroperitoneal tumors than for other sites: sacrum and coccyx, heart, neck, mediastinum, and abdomen. Evaluation of chemotherapy in teratomas with significant immature components is difficult because few of the patients of this small sample received such treatment. As in other sites, regardless of the degree of maturity, exeresis must be as complete as possible.