Necropsy reports of 13 patients with 15 cavitary lesions situated close aortic or mitral valve rings were studied in patients who ranged in age from 1 month to 57 (mean 24.9) years; 10 patients were male. Infective endocarditis occurred in 7 patients, rheumatic heart disease in 4, congenital heart diseases in 4, previous valve replacement in 4, and syphilis in 1 patient. Diameters of the cavitary lesions ranged between 1.2 and 10.5 cm; the aortic valve ring was involved in 11 patients; cavitary thrombosis occurred in 2 cases; the orifice communicating the cardiac chamber with the cavitary lesions was situated above the aortic leaflet in 5 lesions, below the aortic leaflet in 4 lesions, and above and below the aortic leaflets in 3 lesions. The mitral valve ring was involved in 3 lesions. Thus, different etiologies may be involved in the pathogenesis of these lesions; positions of the lesion may vary in relation to the valve ring, and the lesions may be a morphological expression of the fragility of the fibrous skeleton of the heart.