A case of posttherapeutic sclerotic change of bone metastasis from renal cell carcinoma which proved histopathologically to be complete response.

A 60-year-old man with renal cell carcinoma and metastases to the right 7th rib and L2 vertebra (T2N0M1, OSS) was treated with interferon-alpha and the uracil and tegafur combination following nephrectomy. One and a half years later on bone scintigraphy, the abnormal accumulation had disappeared at the L2 vertebra and weakened in its intensity at the right 7th rib. Plain X-ray revealed that the metastatic lesion at the right 7th rib had decreased in size and had been replaced by calcification. The right 7th rib was removed surgically and step-sectioned pathological specimens revealed necrosis with no viable cancer cells.