CEMENTED TUNGSTEN CARBIDE PNEUMOCONIOSIS

An autopsy case of cemented tungsten carbide pneumoconiosis, the first lethal case in our country, is presented. A 28‐year‐old woman, who had been engaged in grinding presintered metallic matrix for four years, developed respiratory symptoms. X‐ray examinations were indicative of interstitial pulmonary fibrosis. Corticosteroid therapy revealed only little effect. She expired five years after the onset of the symptoms. Postmortem examination showed nonspecific interstitial pneumonitis resulting in marked lung fibrosis. Ultrastructurally, crystals were observed in cytoplasm of presumable macrophages in the fibrotic lung tissue. Electron probe microanalysis of the lung tissue showed the presence of tungsten and other constituents of tungsten carbide except for cobalt. Metal analysis demonstrated a large amount of tungsten in the lung. Cobalt was detected tenfold of the normal value in the bone. In pathogenesis of the pneumoconiosis in the cemented tungsten carbide workers, toxicity of cobalt is most suspectable, and in addition, individual susceptibility may be also important.