Teratomas in childhood.

Of 107 teratomas in children, 86 were benign and 21 malignant. Sacrococcygeal and pelvic teratomas predominated (51 cases) and these fell into 3 groups: post sacral, dumb-bell and presacral. The 34 purely posterior tumours were always congenital and benign, whilst the incidence of malignancy in dumb-bell and presacral teratomas increased as the tumour became more internal. Malignant teratomas were carcinomas, usually containing glandular, papillary and clear-cell areas, and metastases were similar. Immature tissues in benign teratomas were usually neural or connective tissue. They did not give rise to neuroblastomas or sarcomas, and did not indicate a worse prognosis. Only 2 originally benign teratomas later developed malignancy.