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 have reported systemic sarcoidosis with cutaneous manifestations in which polarizable particles were associated with granuloma formation in the skin. We searched the biopsy specimens of granulomatous lesions from 50 patients with cutaneous sarcoidosis using polarization microscopy to estimate the frequency of polarizable foreign bodies in cutaneous lesions of sarcoidosis. Using electron-probe microanalysis, we sought to determine what elements compose these foreign bodies. Polarizable foreign bodies were found in the granulomatous 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. Polarizable foreign bodies were found in two cases. The elements identified were calcium, phosphorus, silicon, and aluminum. Polarizable foreign bodies were found in cutaneous sarcoidosis far more often than expected. Foreign bodies were also found in granulomatous systemic lesions. The foreign body may serve as an inciting stimulus for granuloma formation in selected cases of sarcoidosis.