The parenchymal lung diseases caused by metal inhalation include interstitial fibrosis, giant cell interstitial pneumonitis, chemical pneumonitis, and granulomatous disease, among others. We reported two cases of granulomatous lung disease with occupational exposure to metal dusts other than beryllium. They had worked in the battery manufacturing industry for 7 years and in an aluminum-processing factory for 6 years, respectively. Chest high-resolution computed tomography showed diffuse micronodules, and histology of video-assisted lung biopsy specimens revealed granulomatous lesions in the pulmonary interstitium. Results of microscopic examination of the tissue with special stains for mycobacteria and fungi were negative. Analysis by an electron probe microanalyzer with a wavelength-dispersive spectrometer (EPMA-WDS) confirmed the presence of silicon, iron, aluminum, and titanium in the granulomas. In particular, aluminum was distributed in a relatively high concentration in the granulomatous lesions. Although chronic beryllium disease is well known as an occupational granulomatous lung disease, much less is known about the other metals that cause granulomatous reactions in humans. Our report pointed out manifestations similar to beryllium disease after other metal dust exposures, in particular aluminum exposure. To our knowledge, this is the first report showing two-dimensional images of elemental mapping in granulomatous lesions associated with metal inhalation using EPMA-WDS.
Keywords: ACE, angiotensin converting enzyme; Aluminum dust; BAL, bronchoalveolar lavage; DLco, carbon monoxide diffusing capacity; EPMA, electron probe microanalyzer; Elemental analysis; Granulomatosis; HRCT, high-resolution CT; Occupational lung disease; PPD, purified protein derivative; SP-D, surfactant protein D; Sarcoidosis; VC, vital capacity; WDS, wavelength dispersive spectrometer.