Pulmonary embolism in patients with acute leukemia and severe thrombocytopenia.

While pulmonary thromboembolism has been reported in patients with acute leukemia complicated by severe thrombocytopenia, it has been studied infrequently and its pathogenesis remains imprecisely understood. Findings of 80 consecutive autopsies of patients with acute leukemia showed that three had pulmonary thromboembolism. All three patients had been severely thrombocytopenic and had received numerous platelet transfusions. Serial sections of thrombi were evaluated with electron microscopy. In no instance were platelet aggregates detected. However, Candida organisms were prominent in thrombotic specimens from each patient. These findings suggest that thromboembolism in such patients may involve occult fungal infection. Because pulmonary thromboembolism can complicate the course of acute leukemia and severe thrombocytopenia, it should be considered when clinical data suggest its occurrence.