Congenital sacrococcygeal teratomas: effect of gestational age on size, morphologic pattern, ploidy, p53, and ret expression.

Prognosis of infants born with sacrococcygeal teratomas (SCTs) correlates with gestational age (GA). The survival rate after 30 weeks of gestation is 75%, compared to 7% before 30 weeks of gestation. Studies correlating GA with size, morphologic composition of teratomas, ploidy or expression of cell cycle control proteins such as p53, and ret [a tyrosine kinase receptor of the GDNF (glial cell line-derived neurotrophic factors)] receptor family may provide information explaining differences in survival. Seven SCTs (GA 21 to 41 weeks), ranging in size from 5 to 15 cm, were evaluated for morphologic composition. DNA ploidy was assessed in mature and immature neural elements. Immunohistochemical reactivity with monoclonal antibodies recognizing p53, and ret was quantitated and correlated with morphological pattern and GA. Relative size of teratomas to infants' weight and content of immature neural tissues correlated inversely with advancement of GA. Yolk sac tumor (YST) and immature tissues showed aneuploid cell populations. Nuclear p53 reactivity was apparent in the teratoma with YST in the microcystic patterns, the neuroectodermal rosettes, and the glandular patterns. Ret reactivity was seen in osteoclasts adjacent to bone formation surrounding developing teeth in an immature teratoma, and in rare mature neural cells of one SCT of 35 weeks GA. The rapid growth of SCT (GA <30 weeks) correlates with increase in immature neural tissues. Our study confirms aneuploidy in YST and suggests aneuploid populations within immature tissues. p53 accumulates in a variety of patterns of YST and may be seen in immature components of SCTs. To understand the possible role of ret, further studies comparing ret expression in immature human tissues are needed.