Pulmonary heart disease resulting from thrombotic occlusion of the small pulmonary arteries due to repeated "silent emboli" has been recognized for some time. Owen and co-workers1 have reported 12 cases of this rather rare condition in its purest form, uncomplicated by other serious disease, among 8,000 autopsies within a period of 20 years. The ages of the patients ranged from 32 to 72. According to Parker and Smith,2 the occurrence of embolic phenomena is unusual before the fourth decade. In a series of 97 cases of fatal pulmonary embolism reported by Fowler and Bollinger,3 81% occurred in the group over 40 years of age, the median age group being 60 to 70. The case presented here appears to involve one of the youngest patients yet reported with massive pulmonary embolism. A similar case in an 18-year-old athlete has been reported by Neuhof and Klein.4 Report of