Adult T cell leukemia lymphoma (ATL) localized in the right tibial bone

A 56-year-old man was admitted complaining of pain in the right tibia. He w as diagnosed as having adult T-cell leukemia/lymphoma (ATL/L) in the right knee joint by roentgenographic and histological examination. Monoclonal int egration of HTLV-I proviral DNA was demonstrated in the bone tumor cells, a lthough polyclonal integration was observed in the peripheral blood. These results led us to make a diagnosis of ATL with localized growth in the righ t knee joint. The osteolytic bone change was progressive despite radiation therapy. Complete remission was achieved after amputation of his right lowe r leg and two courses of chemotherapy. Resection of the localized lesion mi ght be useful in cases of ATL, but further studies are necessary to confirm this conclusion.