Cortical bone metastases.

The data on 26 patients with solitary metastatic lesions arising in cortical bone were studied. Nineteen patients were over 50 years of age. In 19 patients, the cortical metastasis was the first indication of the presence of a primary malignant condition. In seven cases, cortical metastases developed in patients with a known primary tumor. The primary tumors involved were eight renal cell carcinomas, six bronchogenic carcinomas, two carcinomas of the gastrointestinal tract, one osteosarcoma, one neuroblastoma, one melanoma, one hepatoma, one carcinoma of the breast, and one thyroid carcinoma. In four cases, the primary tumor remained unknown. A metastatic origin should be considered in the differential diagnosis of an osteolytic lesion arising in the cortex of a long bone, especially in older patients and in patients with a known primary malignant condition. The cortical bone metastases encountered in this study did not originate solely from bronchogenic carcinoma, as has been reported by other authors. Cortical metastases are probably less rare than has been hitherto assumed.