Germ cell tumors of the sacrococcygeal region: radiologic-pathologic correlation.

Germ cell tumors of the sacrococcygeal region include mature and immature teratomas and endodermal sinus tumor. Most sacrococcygeal teratomas are discovered in the newborn period as an obvious mass, but they may be detected prenatally. Endodermal sinus tumors are usually discovered later in early childhood. Pathologically and radiologically, teratomas are either both cystic and solid, predominantly cystic, or rarely solid. Over 50% have calcification or ossification. Most malignant teratomas have substantial solid components and may contain calcification. Treatment is surgical excision including coccygectomy. Malignant tumors are treated with both surgery and chemotherapy. Prognosis is excellent for teratoma, although local recurrences may occur. Malignant teratomas have had a dismal prognosis in the past, which has been improved with multiagent chemotherapy.