Nephroblastoma vs. Malignant Teratoma
Left picture: Because the contrast collections within the mass are parts of the pyelocaliceal system, a nephrogenic tumor is present here, and due to the age of the patient, most probably a nephroblastoma. This malignancy becomes smaller following cytostatic treatment (third picture from the top). Right picture: Due to the additional work-up examination with contrast the mass does not deal with a nephrogenic tumor what is also confirmed by a follow-up CT after surgery at the bottom with presentation of two normal kindneys. In fact this young infant had a retroperitoneal malignant teratoma with a relapse following surgery.
Left picture: 5.5-year-old boy with a palpable abdominal tumor. The CT shows a large mass lying opposite the right kidney. The tumor has an inhomogeneous structure, occupies half of the abdomen and reaches to the midline. Following intravenous contrast application circumscript collections of contrast are visible within the mass (second picture from the top). CT on follow-up (third picture from the top): Following cytostatic treatment, the mass is decreasing. Right picture: CT of a 2 months old boy with a visible and palpable abdominal tumor. The quite homogeneous mass which takes more than the half of the left abdomen lies somewhat higher than the tumor in the contralateral case. Accordingly the right kidney is not recognizable and a larger part of the liver is depicted. Following contrast application (here not shown) no contrast-containing structures are demonstrated within the tumor.