Granulomas containing acicular crystals, usually identified histologically as cholesterol, were found at necropsy in the lungs of twelve patients. A review of the clinical records and the pathologic study of the hearts and pulmonary vessels of these patients at necropsy showed that each of them had had pulmonary hypertension. Two had severe parenchymal pulmonary disease; cholesterol pneumonia was found in one and sarcoidosis in the other. Of the remaining ten patients, none of whom had significant parenchymal pulmonary disease, five had congenital cardiac malformations with shunts, two had valvular lesions, predominantly mitral stenosis, and three had primary pulmonary hypertension. The crystals, obtained by microdissection from the pulmonary granulomas of one patient, were identified by x-ray diffraction analysis as cholesteryl palmitate and/or stearate, and not free cholesterol. Possible causes of the cholesterol-ester granulomas were discussed. Pulmonary hypertension appears to be most important in the pathogenesis since it was the only factor recognized in all twelve patients, and since these granulomas have not been observed at necropsy in the lungs of any patient at the National Heart Institute who did not have pulmonary hypertension. © 1968.
