Foreign bodies in sarcoidosis

Sarcoidosis is a multisystem disease of unknown etiology. The demonstration of polarizable foreign bodies in cutaneous granulomas is generally thought to exclude a diagnosis of sarcoidosis. Nevertheless, some investigators ha ve reported systemic sarcoidosis with cutaneous manifestations in which pol arizable particles were associated with granuloma formation in the skin. We searched the biopsy specimens of granulomatous lesions from 50 patients wi th cutaneous sarcoidosis using polarization microscopy to estimate the freq uency of polarizable foreign bodies in cutaneous lesions of sarcoidosis. Us ing electron-probe microanalysis, we sought to determine what elements comp ose these foreign bodies. Polarizable foreign bodies were found in the gran ulomatous skin lesions of 12 of 50 patients with cutaneous sarcoidosis. All 12 patients also had at least one other granulomatous systemic lesion, and 4 had biopsy specimens of a systemic lesion available for review. Polariza ble foreign bodies were found in two cases. The elements identified were ca lcium, phosphorus, silicon, and aluminum. Polarizable foreign bodies were f ound in cutaneous sarcoidosis far more often than expected. Foreign bodies were also found in granulomatous systemic lesions. The foreign body may ser ve as an inciting stimulus for granuloma formation in selected cases of sar coidosis.