Though the exact etiology of most SCTs is unknown, the majority are thought to be sporadic. A few families with autosomal dominantly inherited presacral teratomas have been described in the literature, however. These masses possess both cystic and solid components. About 80 per cent occur in girls, but it is more often malignant in boys. A substantial number have been encountered in twins.
Most cases are asymptomatic in utero and diagnosed after birth.
Massive hemorrhage into the tumor with secondary fetal exsanguination sometimes occurred spontaneously in utero or was precipitated by labor and delivery. Dystocia, secondary to tumor bulk or tumor rupture, some- times complicated delivery. Sacrococcygeal teratomas should be excised as soon as possible, because small, undifferentiated foci may proliferate and become aggressive. If diagnosed in utero, then intrauterine resection is recommended. Since the tumors are attached to the coccyx, the entire coccyx must be removed.