[Light-chain plasmacytoma with reversible renal insufficiency after intravascular application of thorotrast (author's...

Thirty-three years after intravascular injection of Thorotrast, a light-chain plasmacytoma with hypercalcemia and renal insufficiency was diagnosed in a 60-year-old man. The question of causal relation between Thorotrast deposit and plasmacytoma is discussed. The accumulated radiation load to the bone-marrow as caused by thorium dioxide deposition amounts to circa 3000 rem. According to casuistic and epidemiological communications, induction of plasmacytomas by external X-irradiation may be regarded as possible. A distinct increase in myeloproliferative diseases but only small numbers of plasmacytomas are reported in extensive epidemiological Thorotrast studies. From combination of results of the three most comprehensive epidemiological Thorotrast studies is obtained a numerical ratio of 1:5 for the spontaneous rate against the number of plasmacytomas observed. Identical correlations are yielded by investigations at Hiroshima and Nagasaki. Hence it is to be supposed that also plasmacytomas can be induced by thorotrastosis of the reticulohistiocytic system.