RARE-EARTH (CERIUM OXIDE) PNEUMOCONIOSIS - ANALYTICAL SCANNING ELECTRON-MICROSCOPY AND LITERATURE-REVIEW

Rare earth pneumoconiosis is an uncommonly reported disease caused by the inhalation of dust containing lanthanides, also known as rare eart h metals, which are common industrial materials. The pathologic manife stations and natural history of this disorder are incompletely underst ood, We describe a male patient with a 35-year history of optical lens grinding, an occupation associated with exposure to cerium oxide, a r are earth metal-containing compound. The patient presented with progre ssive dyspnea and an interstitial pattern on chest X-ray; open lung bi opsy showed interstitial fibrosis histologically indistinguishable fro m usual interstitial pneumonitis, However, scanning electron microscop y with energy-dispersive X-ray analysis demonstrated numerous particul ate deposits in the lung, of which the majority contained the rare ear th metal cerium alone or in combination with other elements, Our case is one of the first to describe rare earth pneumoconiosis associated w ith pulmonary fibrosis in the occupational setting of optical lens man ufacture. Resides reinforcing the contention that rare earth metals ar e potentially harmful, our case suggests that such agents may be causa lly related to the development of pulmonary fibrosis.