[Acute respiratory failure resulting from diffuse microscopic pulmonary tumor emboli by bladder cancer: a case diagnosed at autopsy].

A 71-year-old man who had undergone a total cystectomy and a transureterocutaneostomy more than a year earlier was admitted to our hospital on February, 1992 because of the chief complaints of anorexia and systemic bone pain due to multiple bone metastases of bladder cancer. At two weeks after the admission, he had a sudden attack of dyspnea. His chest reontgenogram revealed no significant abnormalities. He had repeated attacks and died of respiratory failure two days after the first attack. An autopsy disclosed diffuse microscopic pulmonary tumor emboli in the pulmonary arteries and arterioles of bilateral lungs, but there was no parenchymal metastasis. The metastatic lesions in the sinusoids of the liver were also occupied by numerous tumor emboli, suggesting that the tumor emboli in the lungs had derived from those in the sinusoids. Microembolization of the whole lung area must be considered as a cause of clinically unexplained dyspnea.