A Primary Pulmonary Sarcoma in a Rhesus Monkey after Inhalation of Plutonium Dioxide

A pulmonary fibrosarcoma of bronchial origin was discovered in a Rhesus monkey that died of pulmonary fibrosis 9 years after inhalation of plutonium-239 dioxide and with a radiation dose to lung of 1400 rad (14 Gy). It grew around the major bronchus of the right cardiac lung lobe and extended into the bronchial lumen and into surrounding pulmonary parenchyma. It also readily invaded muscular pulmonary arteries, resulting in infarction and scarring in the right cardiac lobe. Despite this aggressive growth, the tumor did not metastasize. The primary cause of death was severe pulmonary fibrosis involving the alveolar septa and perivascular and peribronchial interstitium. Bullous or pericitrical emphysema was prominent. The initial lung burden of plutonium in this monkey was 270 nCi (10 kBq) which is equivalent to ∼500 times the maximum permissible lung burden for man on a radioactivity per unit body weight basis. The time-dose relationship for survival is consistent with that of dogs and baboons that inhaled plutonium dioxide and died with lung tumors.