Pathologic spectrum and lung dust burden in giant cell interstitial pneumonia (hard metal disease/cobalt pneumonitis): review of 100 cases.

Hard metal disease (HMD), the interstitial lung disease caused by dusts in the cemented tungsten carbide (WC) industry, has been attributed to cobalt. The rare histologic pattern of giant cell interstitial pneumonia (GIP) is characteristic in HMD. The authors reviewed the history of HMD and 100 cases of HMD that they have seen over 5 decades. GIP was proven in 59; analysis of the lung inorganic particle burden by scanning electron microscopy and energy-dispersive x-ray spectroscopy confirmed HMD in the other 41. Cases have been diagnosed by bronchoalveolar lavage, lung biopsy, and autopsy. Histopathology findings range from focal peribronchiolar inflammation to diffuse interstitial fibrosis and honeycombing. GIP cases in the WC industry reveal elevated concentrations of tungsten in all, but cobalt was detected in only 6 ( approximately 10%). Of the 746 diverse cases in the authors' analytical database, almost all cases with the highest tungsten concentration showed GIP. This study confirms that GIP is effectively pathognomonic for HMD.