This report describes a newborn with a large mediastinal teratoma (MT) pres
enting with severe respiratory distress (RD) at birth. At operation, there
was no space for dissection because the huge cystic and solid tumor complet
ely occupied the left hemithorax. After evacuation of the cystic component,
the tumor was removed successfully. To our knowledge, only 16 newborn infa
nts with MT presenting with RD have been reported. Operative morbidities oc
curred in one-half of the cases. We have reviewed the literature to discuss
the potential risks of this entity.