Use of talc and sarcoidosis - Pathogenic role of cutaneous talc exposure on sarcoidosis

Introduction We report on two patients with sarcoidosis with disseminated nodes, who used talc on irritated cutaneous areas. Case report A histologic examination with intense polarised light showed up cristalline bi-refringent particles within vessels in contact with granulomatous areas. Microdissection followed by an electronic microscopy study and microanalysis was realised. In situ microanalysis allowed us to identify birefringent particles with a size of roughly 0.25mum as silica or silicate coming possibly from talc. We consequently studied a brand name talc. The diffraction spectrum showed that this product not only contained talc but also chlorite and quartz. Electron microscopy examination showed particles of all sizes even smaller than 0.25mum. These infra-microscopic particles, visible in a vessel only when agglomerated, could be invisible under optic microscopy (resolution: roughly Hum) inside the granuloma even though they are responsible for it. Moreover, at this level of size of particles, they may escape mineralogic analyses which use methods involving the destruction of organic material, the mineral residue collecting on cellulose filter with a diameter generally of 0.45 mum. Conclusion Two recent epidemiologic studies confirm the possible role of mineral exposure in sarcoidosis. Some sarcoidosis could be caused by mineral overload on genetically predisposed patients. Some cases could be related to mineral powder application. Among different types of mineral exposure, applications of cosmetic products may induce disseminated granulonnatous reaction on genetically predisposed patients. Such applications have to be considered in epidemiologic studies.