The pathogenesis of eosinophilic endomyocardial disease in patients with carcinomas of the lung.

Studies were done on a patient with a carcinoma of the lung induced by hypereosinophilia who was thought to be at risk from developing eosinophilic endomyocardial disease to see whether the development of heart disease could be related to abnormalities in the morphology or kinetics of blood eosinophils. The patient was a 61-year-old man who had a partial resection of a squamous cell bronchial carcinoma of anaplastic large cell type which has spread locally. Seven months later, he developed a blood eosinophil count of 33.9 x 10(9)/1. There were only transient responses to treatment with steroids and tumor irradiation, and he died 15 weeks later. Up to 3 x 10(9)/1 blood eosinophils were degranulated, correlating with serum levels of eosinophil cationic protein. The blood half-life of 111indium-labeled eosinophils was prolonged to 53 h, but their distribution was normal. Although an unsuccessful search was made during life for the development of endomyocardial damage, at postmortem the left ventricle had features of eosinophilic endomyocardial disease in the acute necrotic stage. Among 13 other reported patients with carcinoma of the lung and hypereosinophilia, three also had endomyocardial disease or myocardial lesions. These findings confirm the suggestion that the presence in the blood of greater than 1 x 10(9)/1 degranulated eosinophils can be used to predict the development of eosinophilic endomyocardial disease before it becomes apparent clinically, and they also add weight to the hypothesis that blood eosinophil degranulation causes this complication of hypereosinophilic states.