[A case of hard metal lung disease in a man who worked as an iron grinder]

The patient was a man who had suffered from repeated pneumothoraces since August 2003, when he was 16 years old. A right pneumothorax was observed at age 21 years, in April 2008. At the same time, a dry cough began to appear and diffuse small nodular shadows in both lung fields were found on a chest X-ray film. Due to worsening symptoms and the chest X-ray findings, a transbronchial lung biopsy was performed in September 2008. Pathological examination showed mural type organization, and large numbers of multinucleated giant cells that were engulfing nucleated cells and had black pigment in their cytoplasm. Giant cell interstitial pneumonia and hard metal lung disease (HMLD) were suspected because of the patient's occupational history as a metal grinder, which included the use of a hard metal tool for three years since August 2005. In an elementary analysis using an electron probe microanalyzer, tungsten was detected in resected lung tissue obtained in April 2008 which confirmed the diagnosis. His symptoms improved after the initiation of corticosteroid therapy, which continued but with a gradual decrease in the dose. In this case, HMLD developed over a relatively short period despite the low level of dust dispersal of a hard-metal tool, perhaps because of a hypersensitivity of the patient to hard metal.