Foreign bodies in granulomatous cutaneous lesions of patients with systemic sarcoidosis.

OBJECTIVE To assess the presence of foreign material in the granulomatous cutaneous lesions of patients with systemic sarcoidosis. DESIGN AND SETTING Observational study reevaluating histological specimens at a university referral hospital. PATIENTS Sixty-five patients diagnosed as having sarcoidosis who developed granulomatous cutaneous involvement. MAIN OUTCOME MEASURES To detect the presence of polarizable foreign particles in cutaneous biopsy specimens and to evaluate the association with clinical features of the patients. RESULTS Granulomatous cutaneous involvement was demonstrated in 65 (15.3%) of 425 patients with systemic sarcoidosis. In 14 (22%) of the 65 patients, the cutaneous biopsy specimen showed foreign particles in polarized light. The skin lesions corresponded to 3 different clinical patterns: an admixture of papules and infiltration of previously undetected minute scars (n = 6); scar sarcoidosis (n = 4); and subcutaneous nodules (n = 4). The lesions were located most frequently in the extremities, involving the knees in 10 patients. CONCLUSIONS The presence of polarizable foreign body material in granulomatous cutaneous lesions is not infrequent in patients with systemic sarcoidosis. Inoculation of foreign matter from a previous inapparent minor trauma may induce granuloma formation in individuals with sarcoidosis.