Diffuse Interstitial Fibrosis in Nonasbestos Pneumoconiosis – A Pathological Study

Abstract

Pathological examinations of 233 consecutive autopsy cases with nonasbestos pneumoconiosis revealed evidence of diffuse interstitial fibrosis (DIF) in 64 (27.5%), among whom 45 (19.3%) showed bilateral involvement and 9 (3.9%) extensive disease closely resembling usual interstitial pneumonia. The patients with DIF were significantly older and had longer occupational histories as compared with those without DIF. There was no correlation between the occurrence of DIF and the type of the underlying disease (silicosis or mixed dust pneumoconiosis) except that an extensive DIF was more frequently associated with mixed dust pneumoconiosis. The extensive DIF developed an in situ malignancy much more frequently (33.3%) than the focal disease (2.6%).

Silica exposure and systemic vasculitis.

“…Irregular opacities in the bases of the lungs, with pleural thickening, that were detected by the case patient's chest CT scan are consistent with asbestos-related lung disease (Churg 1998;Rom 1998), silicosis and mixeddust pneumoconiosis (Honma and Chiyotani 1993;Shida et al 1996), idiopathic pulmonary fibrosis, and smoking tobacco (Dick et al 1992). Although silicosis is classically described as rounded opacities in the upper lobes, some studies and reviews of the literature describe a less classical finding of irregular opacities in the lower lobes (Dick et al 1992;Gibbs and Wagner 1998).…”

“…Two cases were associated with collagen disease, one case was associated with systemic sclerosis, and one was associated with rheumatoid arthritis. In addition, no significant correlation was found between the occurrence of DIF and smoking history (Honma and Chiyotani 1993 the literature that systemic vasculitides may develop independently of silicosis in patients with crystalline silica exposure. Epidemiologic studies link solvent exposure to an increased risk of systemic sclerosis but not systemic pANCA-positive vasculitis.…”

“…Although silicosis is classically described as rounded opacities in the upper lobes, some studies and reviews of the literature describe a less classical finding of irregular opacities in the lower lobes (Dick et al 1992;Gibbs and Wagner 1998). Honma and Chiyotani (1993) described diffuse interstitial fibrosis (DIF) among workers with a variety of occupations (rock driller, stone mason, metal miner, tunneler, construction worker). The cases were diagnosed pathologically as silicosis (142 cases) or mixed dust pneumoconiosis (91 cases); the diffuse interstitial fibrosis was predominantly in the lower lobes and thickening and adhesion of the pleura covering the DIF was seen in 40.6% of the cases.…”

Delayed development of silicoproteinosis with diffuse interstitial fibrosis: 16-year follow-up with autopsy correlation

“…The reason for delayed progression of silicoproteinosis is unknown, but it might be associated with the excellent lymphatic clearance for dusty occupations. Another important finding of this case was the presence of diffuse interstitial fibrosis, which was different from the UIP pattern with honeycombing, reported in silicosis [3]. The lymphatic clearance was supposed to have been overwhelmed as indicated by the presence of eggshell calcification in the lymph nodes.…”

Asbestos exposure increases the incidence of histologically confirmed usual interstitial pneumonia

“…Some occupations are also risk factors for IPF, especially for pneumoconiosis, at up to 28% . In the report of Gaensler, the incidence of IPF in asbestos‐exposed workers was 5%, which seems to be higher than its incidence in the general population, and the mean number of amosite + crocidolite fibres was six times higher than in controls.…”