PMC4524026_01
High-resolution computed tomography (HRCT) findings before and after the avoidance of dust exposure in Case1. Bilateral diffuse centrilobular micronodular opacities and curved linear shadows in the dorsum. a: before the avoidance (a-1: upper lobe; a-2: lower lobe); b: after the avoidance (b-1: upper lobe; b-2: lower lobe)
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Fig1
High-resolution computed tomography (HRCT) of the chest showed diffuse centrilobular micronodular opacities and curved linear shadows in the dorsum (Fig. 1a).
Histological findings from biopsy specimens in Case 1. Peribronchiolar fibrosis and lymphocytic infiltration are marked, but multinucleated giant cells are barely apparent (a: hematoxylin and eosin [HE] stain x 100; b: HE x 400)
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Fig2
Although a few multinucleated giant cells were observed, no features diagnostic of GIP were evident (Fig. 2).
Images of EPMA in Case 1. The presence of tungsten and cobalt in the peribronchial fibrotic region was observed (a: HE stain; b: tungsten; c: cobalt)
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Fig3
Elemental analysis of the lung tissue using an electron probe microanalyzer with a wavelength-dispersive spectrometer (EPMA-1610; Shimadzu Ltd, Kyoto, Japan) revealed the presence of tungsten and cobalt in the peribronchial fibrotic region (Fig. 3).
Serial changes in pulmonary function in Case 1. a: vital capacity (VC), b: forced expiratory volume in 1 s (FEV1), c: total lung capacity (TLC), d: diffusing capacity of the lung for carbon monoxide (%DLCO)
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Fig4
A series of pulmonary function tests revealed continuous improvements over the course of 30 months without exposure to hard metal dust (Fig. 4), although improvements in HRCT findings were modest (Fig. 1b).
PMC4524026_02
HRCT findings before and after the avoidance of exposure in Case 2. Bilateral diffuse centrilobular micronodular opacities and reticular shadows. a: before the avoidance (a-1: upper lobe; a-2: lower lobe); b: after the avoidance (b-1: upper lobe; b-2: lower lobe)
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Fig5
Chest HRCT showed diffuse centrilobular micronodular and reticular shadows (Fig. 5a).
Histological findings from biopsy specimens in Case 2. Marked peribronchiolar fibrosis accompanies multinucleated giant cells in the bronchioles and alveoli (a: HE stain x 100; b: HE stain x 400)
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Fig6
VATS of the left upper and lower lobes were performed, and histopathological examination revealed interstitial fibrosis accompanied by multinucleated giant cell infiltration into peribronchiolar and alveolar tissues, leading to a diagnosis of GIP (Fig. 6).
Images of EPMA in Case 2. The presence of tungsten in the bronchioles and alveoli was observed (a: HE stain; b: tungsten)
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Fig7
Elemental analysis of the lung tissue revealed the presence of tungsten in the bronchioles and alveoli (Fig. 7), and XAFS analysis confirmed the presence of tungsten carbide (data not shown), thus leading to the clinical diagnosis of HMLD.
Serial changes in pulmonary function in Case 2. a: VC; b: FEV1; c: TLC; d: %DLCO
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Fig8
Although a series of pulmonary function tests revealed improvements over the course of a year (Fig. 8), improvements in HRCT findings were modest (Fig. 5b).