Heron Werner, MD & Pedro Daltro, MD
Clínica de Diagnóstico por Imagem (CDPI) & Instituto Fernandes Figueira (IFF) – FIOCRUZRio de Janeiro – Brazil

Dorothy I. Bulas M.D.
Professor of Radiology and Pediatrics
Children"s National Medical Center
George Washington University Medical Center
111 Michigan Ave, NW,   Washington D.C. 20010

The sacrococcygeal teratoma is defined as a neoplasm composed of tissues from all three germ layers. Commonest sites are the sacrococyx, although they may occur near the midline from the brain to the coccyx. It is the most common tumors in newborns (1/35,000 to 1/40,000 live births), and it is more common in females than males (4:1).

The American Academy of Pediatrics classifies the sacrococcygeal teratoma in four types:

• I: Completely external; no presacral component
• II: External component and internal pelvic component
• III: External component and internal component extending into abdomen
• IV: Completely internal and no external component.

Most of these tumors are solid or mixed solid and cystic. Polyhydramnios is a common sign and non-immune hydrops have also been seen in association. The differential diagnosis includes lumbosacral myelomeningocele, hemangioma, neurofibroma, lipoma, etc. The prevalence of malignancy when the diagnosis is done less than 2 months after birth is 10%, but the diagnosis after 2 months of age can increase the frequency of malignancy more than 50%. The benign neoplasm can transform into malignancy. So, the surgical removal is advisable.