Sarcoidosis, light micrograph. Sarcoidosis is a chronic disease of unknown cause characterised by the presence of nonnecrotising granulomas in various organs and tissues. Involvement of the heart can result in conduction disturbances, arrhythmias, congestive heart failure, and even sudden death. This high magnification view shows a single epithelioid granuloma with several multinucleated giant cells, histiocytes, and lymphocytes.