Radiographic manifestations of bone metastases from renal carcinoma.

From 1964 to 1974, 1,668 patients with renal carcinoma were seen at the Mayo Clinic. Bone metastases were present in 167 of these patients (only lung metastatic involvement ranked higher in frequency). More than one-third of the patients with bone metastasis from renal carcinoma had this as a presenting lesion of occult renal tumor. This group constituted 4% of all patients with renal carcinoma evaluated during the study period. While most bone lesions were in the pelvis and lower lumbar spine, any bone may be involved. All patients with bone metastases from renal carcinoma have a poor prognosis. However, some bone lesions appeared as long as 10 or more years after the initial tumor. The most common radiographic features are a lytic destructive process with indistinct margins, erosion of the cortex, and frequent expansion into the soft tissues. Pathological features are common in the long bones, and calcifications are occasionally seen. The synovial joints are not affected. A well defined sclerotic margin is a common finding after radiation treatment, although it is not a reliable indicator of the stability of the lesion.