We report on two infants of 11 and 12 months of age, respectively, with large solid-cystic retroperitoneal tumors. Complete resection was achieved, and both children are doing well over a follow-up of more than 17 months. The presented paper focuses on surgical anatomy of this very rare type of tumor. Teratomas were located mainly within the upper abdominal cavity, and both tumors displaced the pancreas in an anterior position. The following anatomical features were observed (1) displacement of surrounding organs, (2) deformation and elongation of large retroperitoneal vessels, (3) fibrous incorporation of large vessels by the tumor pseudocapsule, (4) wrapping of anterior aortic branches by lobes and fingers of the tumor.