[Sacral teratomas--organized forms].

Between 1939 and 1971 31 cases of sacrococcygeal teratomas were observed at Zurich Children's Hospital, in 5 cases the tumor contained well-developed organs. From 1970 to 1982 25 cases of sacrococcygeal teratomas were identified at Teheran Children's Hospital. In 2 of these cases the tumors were organized. At the same time we observed 2 other cases, one a well differentiated retroperitoneal teratoma, the other an ectopic third leg in the lumbosacral region. In the so-called organized teratomas we found all organs with the exception of heart, lung, kidney, eyes and vertebra. Malignant degeneration was not observed. It is probable that such organized tumors develop from a concentration of rich pluripotent cells at the end of the coccyx. An explanation for ectopic extremities could be the deplacement of pluripotent cells at an early stage of embryonic development.