Retroperitoneal teratomas comprise 3.5 – 4% of all germ cell tumors in children. Patients present with abdominal distension or a palpable mass. Occasionally, the tumor is present antenatally and diagnosed at birth.Teratomas may be classified as mature or immature on the basis of the presence of immature neuroectodermal elements within the tumor.An accurate diagnosis of a teratoma cannot be made on clinical basis. 

Radiological features include presence of calcification, teeth and fat, however calcification cannot be considered an indicator of a benign tumor since 12.5% of calcified tumor are malignant. Ultrasound of abdomen is usually the first imaging modality used in pediatric abdominal mass. CT scan is useful to delineate the extent of the disease in retro-peritoneum and its relationship to major vessels.Magnetic resonance imaging (MRI) of the abdomen and pelvis may be substituted for CT.

When a germ cell malignancy is suspected, tumor markers should be assessed prior to surgery. 

-Alpha-fetoprotein (AFP)

-Beta–human chorionic gonadotropin (β-HCG)

-LDH

Serum alpha-feto protein level is good indicator for diagnosis and assessing the recurrence of tumor. Malignancy is uncommon in retro-peritoneal teratoma hence non mutilating excision is possible and should be attempted. The prognosis of neonatal teratoma is favorable with an 80-100% survival reported after surgical excision of the tumor and treatment of any recurrence.

For children with extracranial germ cell tumors, surgery is an essential component of treatment.