Rhabdoid tumors of the kidney in children: CT findings.
OBJECTIVE: The purpose of this study was to identify CT characteristics of rhabdoid tumor of the kidney, a rare, aggressive, malignant neoplasm of unknown origin that occurs mainly in infants and young children. MATERIALS AND METHODS: CT scans of eight children (newborn to 13 years old; mode, 4 months old; six boys and two girls) with histopathologic diagnosis of rhabdoid tumor of the kidney were evaluated retrospectively by two of the authors, who were not blinded to the diagnosis. All eight CT scans were performed with intravenous and oral contrast, and noncontrast intravenous CT scans were available in four cases. The following CT characteristics were evaluated: location of tumor within the kidney; presence of calcification, subcapsular hematoma, multiple tumor lobules, enlarged vessels, vascular invasion, or central tumor necrosis or hemorrhage; visibility of tumor margin; distant metastasis; and primary tumor size. RESULTS: All eight primary tumors (five on the left, one of which had contralateral renal nodules) were central in location and involved the hilum. Calcification outlining the tumor lobule was present in two of the four tumors on noncontrast CT scans. Subcapsular hematoma was seen in five children. Tumor necrosis and hemorrhage were seen in seven children. Tumors were well defined from the renal cortex in four children. Lobules of tumor were seen in seven children. CONCLUSION: CT findings of calcification, subcapsular hematoma, and lobular appearance in a large, centrally located, and heterogeneous renal mass in a child suggest a rhabdoid tumor of the kidney.