Birefringent particles in granulomatous dermatitis, sarcoidal-type, as well as in other non-granulomatous skin disorders in patients without sarcoidosis.

Silica granuloma (SG) is a rare entity in literature. The relationship between SG and sarcoidosis has not always been clear. We tried to find out how common birefringent particles are in cutaneous biopsies from patients with and without sarcoidal granulomas. We studied the most recent 200 skin biopsies that came to our service. We also studied 10 cases of sarcoid-type granulomatous dermatitis. All of them were studied under the polarized light. Quantification of particles was classified from negative to very abundant. We found birefringent particles in 39.5% of the biopsies without a sarcoid-type granulomatous infiltrate. We found birefringent particles in 7 out of the 10 cases of the group with a sarcoid-type cutaneous dermatitis (70%). 5 of the 10 cases presented with systemic sarcoidosis, and from these, 4 presented with birefringent particles (80%). From the other 5 cases, we found birefringent particles in 3 cases (60%). Birefringent particles can be evidenced in the skin biopsy of patients with systemic sarcoidosis in a higher percentage than in non-granulomatous skin biopsies of subjects without a history of sarcoidosis. Therefore, evidence of those particles does not exclude sarcoidosis (Tab. 1, Fig. 4, Ref. 23).