Clear cell sarcoma of the kidney: accuracy of imaging methods for detecting bone metastases. Report from the National Wilms' Tumor Study.

To evaluate the accuracy of various imaging methods to screen for bone metastases in patients with clear cell sarcoma of the kidney (CCSK), all such cases reported on the National Wilms' Tumor studies from 1969-1983 were reviewed. Eighty-two CCSK children were identified, 19 of whom (23%) sustained bone metastases sometime during their course. Thirteen metastatic sites were evaluated by both radiography and bone scanning. In seven instances both modalities were positive; in four the radiography was positive but not the scan; and in only two (15%) was the scan positive in light of a negative radiograph. We recommend both imaging modalities in evaluating children with CCSK in order to detect all metastatic sites in all patients, and to further our observation that "hot" lesions on scintigraphy are more amenable to treatment than "cold" lesions.