Paraseptal Emphysema in Indium Lung: Tracing the Pathological Footprints of Chronic Exposure.

Indium lung is an occupational lung disease caused by exposure to indium-tin-oxide (ITO) dust. Compared to other occupational lung diseases, indium lung has a shorter latency period and the respiratory status continues to worsen even after exposure to the work environment improves. Paraseptal emphysema which affects mainly the subpleural area is seen on chest images obtained via computed tomography (CT), regardless of the smoking history. However, the pathogenesis of emphysema in indium lung is still unclear. Therefore, we re-evaluated the pathology of three previously reported cases of indium lung. Paraseptal emphysema was observed in both smokers and nonsmokers. Obstructive respiratory impairment worsened over time in the cases with paraseptal emphysema. Many alveolar walls were destroyed independent of the presence or absence of emphysetamous changes or fibrosis. Moreover, bronchiolitis was found to be less common in indium lung than in asbestosis (the most common occupational lung disease) or common cases of chronic obstructive pulmonary disease caused by smoking. It has been shown that ITO causes protease anti-protease imbalance, oxidant-antioxidant imbalance, and continuous, abnormal inflammation (the three major causes of emphysema). In addition, nano-sized ITO is less likely to be trapped in the upper airways and may easily reach the subpleural alveoli. Furthermore, ITO may continue to cause sustained tissue injury at the alveolar level potentially resulting in emphysema. Further studies are needed to elucidate the detailed pathogenesis of indium lung by comparing it with other occupational lung diseases.

A case report of Indium lung with progressive emphysema and fibrosis underwent lung unilateral transplantation 20 years after the end of the exposure.

BACKGROUND: Indium lung is characterized by interstitial pneumonia and/or emphysema which occurs in indium-tin oxide (ITO) workers. Indium lung is now known to progress after stopping exposure to ITO, but the long-term influences of ITO remain unclear. CASE PRESENTATION: Forty seven years old, a never-smoker, who had been engaged in an ITO manufacturing process for 8 years. Emphysema was indicated by the medical check-up for ex-ITO workers, and he was diagnosed with indium lung. He underwent partial lung resections for pneumothorax two times, and obstructive pulmonary dysfunction had progressed through the years. He underwent right single lung transplant 20 years after ITO exposure. Pathologically, his lung showed severe distal acinar emphysema and honeycomb change. Fibrosis and destruction of the lung tissue significantly progressed compared to the previous partial resections. Scanning electron microscopy combined with energy dispersive spectroscopy revealed that the deposited particles contained indium and tin. After the transplantation, his respiratory function was improved. CONCLUSIONS: In this case, ITO resided in the lung tissue for 20 years, and lung tissue destruction kept progressing. Careful medical follow-up is recommended for ITO-workers even if they are asymptomatic.

Progression of Smoking-Induced Emphysema in a Case with Indium Lung.

Recently, it has become clear that inhaled indium-tin oxide causes emphysematous as well as interstitial changes in the lung. Here, we present a 59-year-old male ex-smoker, quitting smoking at the age of 55. He had been engaged in indium-tin oxide processing from 27 to 37 years of age, with 22 years having passed since the final exposure to indium. He was found to have a high serum indium concentration and Krebs von den Lungen-6 (KL-6). Furthermore, bilateral centrilobular emphysema was recognized in high-resolution computed tomography (HRCT). After transferring jobs to a non-indium-tin oxide section, KL-6 returned to a normal level within 4 years, whereas neither serum indium concentration nor emphysema had decreased to normal despite 22 years having passed since the exposure ended. At the age of 59, a thoracoscopic lung biopsy was performed to assess the contribution of smoking and that of indium to the lung destruction. The pathological findings demonstrated cholesterol granulomas with the accumulation of macrophages and multinucleated giant cells that had phagocytosed particles. Together with the typical findings of indium lung, fibrotic and emphysematous changes were observed. The elemental analysis of the biopsied specimens revealed excessive deposition of indium throughout the airways, interstitial spaces and alveoli. The pathological findings of this case may be the result of two kinds of pulmonary damage, i.e., smoking and indium. This report indicates that occupationally-inhaled indium could remain in the lung for as long as 22 years and continue to insult the lung tissue with inflammation caused by smoking.

Response to pembrolizumab in a patient with primary lung adenocarcinoma originated from indium lung.

BACKGROUND: Indium is a metal used as a compound called indium-tin oxide for liquid crystal display. Its inhalation causes lung toxicity, resulting in a new occupational lung disease called indium lung. Although the carcinogenicity of indium has been reported in an animal model, its carcinogenicity in humans is unknown. CASE PRESENTATION: This is the first reported case of a primary lung cancer originating from indium lung. In this report, we describe a 46-year-old man with interstitial pneumonia-type indium lung diagnosed 16 years ago. The initial symptom was left chest pain, and computed tomography showed a mass adjacent to the aorta with left pleural effusion. Specimens collected using video-assisted thoracoscopy revealed an adenocarcinoma with a high expression of programmed cell death-ligand 1 (cT4N0M1a stage IVA). Although the lesions showed a remarkable aggressive nature, the patient benefited from pembrolizumab, a monoclonal antibody against programmed cell death 1, which was used as second-line therapy for 2 years. CONCLUSIONS: It is important for clinicians to be aware of lung cancer development in indium-exposed workers or in patients with indium lung, as this could have an aggressive behavior. Treatment with immune checkpoint inhibitors is an option even in patients with interstitial pneumonia-type indium lung.

A case of Marfan syndrome with massive haemoptysis from collaterals of the lateral thoracic artery.

BACKGROUND: Marfan Syndrome (MFS) is a heritable connective tissue disorder with a high degree of clinical variability including respiratory diseases; a rare case of MFS with massive intrathoracic bleeding has been reported recently. CASE PRESENTATION: A 32-year-old man who had been diagnosed with MFS underwent a Bentall operation with artificial valve replacement for aortic dissection and regurgitation of an aortic valve in 2012. Warfarin was started postoperatively, and the dosage was gradually increased until 2017, when the patient was transported to our hospital due to sudden massive haemoptysis. Computed tomography (CT) with a maximum intensity projection (MIP) revealed several giant pulmonary cysts with fluid levels in the apex of the right lung with an abnormal vessel from the right subclavian artery. Transcatheter arterial embolization was performed with angiography and haemostasis was achieved, which suggested that the bleeding vessel was the lateral thoracic artery (LTA) branch. CT taken before the incident indicated thickening of the cystic wall adjacent to the thorax; therefore, it was postulated that the bleeding originated from fragile anastomoses between the LTA and pulmonary or bronchial arteries. It appears that the vessels exhibited inflammation that began postoperatively, which extended to the cysts. CONCLUSION: We experienced a case of MFS with massive haemoptysis from the right LTA. We have to be aware of the possibility that massive haemoptysis could be induced in MFS with inflamed pulmonary cysts.

Indium Lung: Discovery, Pathophysiology and Prevention.

Indium is mainly used as indium-tin oxide (ITO), which has a unique character of transparency, and is a requisite in making liquid crystal displays. Pulmonary toxicity of indium compounds in humans were not recognized until the last 2 decades. Several initial human cases of indium-related lung disease, named indium lung, were reported in Japan, with their main pathologic findings being interstitial pneumonia, emphysema and cholesterol crystals-containing granulomas. In 2010, three cases with alveolar proteinosis were reported from the United States and China. As of March 2019, more than 10 cases of interstitial pneumonia-dominant indium lung have been reported. Cross-sectional studies in indium workers indicate that the serum indium concentration (sIn) is closely related to the exposure period, the extent of interstitial as well as emphysematous changes of the lung on high-resolution computed tomography (HRCT) and serum biomarkers of interstitial pneumonia, including KL-6 and surfactant protein-D (SP-D). Longitudinal studies have shown it is possible to reduce the sIn as well as the interstitial shadows on HRCT; however, emphysematous lesions increased progressively in heavily exposed workers, even after cessation of exposure. Early detection is required to prevent irreversible changes. The first case of lung cancer associated with indium lung developed in a nonsmoking ex-worker. He had been diagnosed with indium lung and stopped working in indium processing 17 years before. This suggested there is a need for appropriate screening to detect for complications of lung cancer at early stages for those with indium lung.

A case of airway aluminosis with likely secondary pleuroparenchymal fibroelastosis.

BACKGROUND: Excessive inhalation of aluminium powder occasionally results in upper lobe predominant lung fibrosis, which is similar to idiopathic pleuroparenchymal fibroelastosis (IPPFE) and has been suggested to be secondary PPFE. CASE PRESENTATION: A 67-year-old man who had worked in an aluminum-processing factory for 50 years visited our hospital complaining of exertional dyspnea. Chest computed tomography (CT) showed bilateral dense sub-pleural consolidation in the upper and middle lung fields, which was consistent with IPPFE; however, the possibility of secondary PPFE associated with aluminosis was not ruled out. Considering the patient's critical condition, trans-bronchial lung biopsy (TBLB) rather than surgical lung biopsy was performed, with elemental analysis of the biopsied specimen. Unfortunately, the specimen obtained by TBLB did not contain alveolar tissue; therefore, pathological diagnosis of PPFE was not possible. However, radiographic findings were highly suggestive of PPFE. On elemental analysis, excessive amounts of aluminum were detected in the bronchiolar walls, establishing a diagnosis of airway aluminosis with likely secondary PPFE resulting from aluminium exposure. CONCLUSIONS: TBLB with elemental analysis might be useful in differentiating idiopathic PPFE from secondary causes in dust inhalation related disease, such as aluminosis. This case indicated that inhalation of aluminium might cause secondary PPFE, with attention needing to be paid to avoid further exposure.

High levels of indium exposure relate to progressive emphysematous changes: a 9-year longitudinal surveillance of indium workers.

BACKGROUND: During the last decade it has been clarified that the inhalation of indium compounds can evoke alveolar proteinosis, cholesterol granuloma, pulmonary fibrosis and emphysema. In this study, we aimed to elucidate the characteristics and time course of pulmonary disorders among indium workers using comprehensive pulmonary examinations at an indium-processing factory. METHODS: Data for 84 male workers who underwent the examinations for nine consecutive years from 2002 to 2010 were analysed regarding their symptoms, serum indium concentration (sIn), serum markers of interstitial pneumonia, pulmonary function test parameters and high-resolution CT (HRCT) findings of the lungs. RESULTS: In association with improvements in the work environment and work practice, the sIn levels decreased with significant reductions in the KL-6 and surfactant protein D (SP-D) levels. Regarding the HRCT findings, the interstitial lesions regressed partially, whereas emphysematous lesions increased progressively in the workers with high sIn values. FEV1/FVC decreased with the years and the rate of decrease was significantly greater in those with high sIn. The biological half-life of sIn was estimated to be 8.09 years. CONCLUSIONS: The present findings suggest that the sIn, SP-D, KL-6 levels and radiological interstitial changes can be reduced in indium workers by alleviating exposure to indium, whereas emphysematous lesions can progress among those with a history of heavy exposure.

A decrease in lung cancer mortality following the introduction of low-dose chest CT screening in Hitachi, Japan.

Recent US clinical trial demonstrated that CT screening prevents lung cancer death among high risk individuals. However, it remains unclear whether wide implementation of low-dose CT screening for lung cancer can decrease mortality in the community. Among residents in Hitachi City (Japan), where nearly 40% of inhabitants aged 50-69 years were estimated to have participated in the screening at least once from 1998 through 2009, the trend of lung cancer mortality was described in relation to the timing of implementation of the CT screening. Cancer mortality data were obtained from regional cancer registry and standardized mortality ratio (SMR) of lung cancer was calculated for each 5-year period during 1995-2009. In both men and women aged 60 years or older, age-specific lung cancer mortality rates were generally lower during 2005-2009 as compared with those during 1995-2004. For combined men and women aged 50-79 years, SMR was nearly unity prior to or during introductory phase of CT screening and during early period of implementation; however, it was significantly decreased during 2005-2009, well after the implementation of CT screening, with SMR (95% confidence interval) being 0.76 (0.67-0.86). Results suggest that wide implementation of low-dose chest CT screening may decrease lung cancer mortality in the community 4-8 years after introduction of the screening.

Prevalence of pulmonary arteriovenous malformations as estimated by low-dose thoracic CT screening.

BACKGROUND: Pulmonary arteriovenous malformations (PAVMs) are rarely encountered in clinical practice. The prevalence of PAVMs associated with hereditary hemorrhagic telangiectasia (HHT) has been estimated based on the rate in the family members of HHT patients, but the prevalence of PAVMs in the general population remains unknown. METHODS: We retrospectively examined the prevalence and clinical characteristics of PAVMs as detected by a low-dose thoracic CT screening program for lung cancer at the Hitachi Medical Center and the Hitachi General Health Care Center in the northern part of Ibaraki Prefecture, Japan. RESULTS: From 2001 to 2007, we identified eight patients (seven females and one male) with PAVMs among 21,235 initial screening participants (the mean age of the patients with PAVMs and that of the screening participants was 60.6 years). The prevalence of PAVMs was estimated at 38 per 100,000 individuals [95% confidence interval (CI)=18-76]. The diameter of the PAVMs was a mean of 6.6 mm, and none of the lesions could be detected by chest X-ray. Females older than 60 years tended to have larger PAVMs than younger women did (p=0.06). Two patients (25%) were diagnosed with HHT. One patient had previously undergone surgery for a brain abscess. CONCLUSION: PAVMs are more prevalent than previously reported, especially among females.

Indium lung disease.

BACKGROUND: Reports of pulmonary fibrosis, emphysema, and, more recently, pulmonary alveolar proteinosis (PAP) in indium workers suggested that workplace exposure to indium compounds caused several different lung diseases. METHODS: To better understand the pathogenesis and natural history of indium lung disease, a detailed, systematic, multidisciplinary analysis of clinical, histopathologic, radiologic, and epidemiologic data for all reported cases and workplaces was undertaken. RESULTS: Ten men (median age, 35 years) who produced, used, or reclaimed indium compounds were diagnosed with interstitial lung disease 4-13 years after first exposure (n = 7) or PAP 1-2 years after first exposure (n = 3). Common pulmonary histopathologic features in these patients included intraalveolar exudate typical of alveolar proteinosis (n = 9), cholesterol clefts and granulomas (n = 10), and fibrosis (n = 9). Two patients with interstitial lung disease had pneumothoraces. Lung disease progressed following cessation of exposure in most patients and was fatal in two. Radiographic data revealed that two patients with PAP subsequently developed fibrosis and one also developed emphysematous changes. Epidemiologic investigations demonstrated the potential for exposure to respirable particles and an excess of lung abnormalities among coworkers. CONCLUSIONS: Occupational exposure to indium compounds was associated with PAP, cholesterol ester crystals and granulomas, pulmonary fibrosis, emphysema, and pneumothoraces. The available evidence suggests exposure to indium compounds causes a novel lung disease that may begin with PAP and progress to include fibrosis and emphysema, and, in some cases, premature death. Prospective studies are needed to better define the natural history and prognosis of this emerging lung disease and identify effective prevention strategies.

Long-term prognosis of patients with lung cancer detected on low-dose chest computed tomography screening.

The effectiveness of lung cancer screening using low-dose chest computed tomography (CT) remains elusive. The present study examined the prognosis of patients with lung cancer detected on CT screening in Japanese men and women. Subjects were 210 patients with primary lung cancer identified on CT screening at two medical facilities in Hitachi, Japan, where a total of 61,914 CT screenings were performed among 25,385 screenees between 1998 and 2006. Prognostic status of these patients was sought by examining medical records at local hospitals, supplemented by vital status information from local government. The 5-year survival rate was estimated according to the characteristics of patients and lung nodule. A total of 203 (97%) patients underwent surgery. During a 5.7-year mean follow-up period, 19 patients died from lung cancer and 6 died from other causes. The estimated 5-year survival rate for all patients and for those on stage IA was 90% and 97%, respectively. Besides cancer stage, smoking and nodule appearance were independent predictors of a poor survival; multivariable-adjusted hazard ratio (95% confidence interval) was 4.7 (1.3, 16.5) for current and past smokers versus nonsmokers and 4.6 (1.6, 13.9) for solid nodule versus others. Even patients with solid shadow had a 5-year survival of 82% if the lesion was 20mm or less in size. Results suggest that lung cancers detected on CT screening are mostly curative. The impact of CT screening on mortality at community level needs to be clarified by monitoring lung cancer deaths.

Indium lung--case reports and epidemiology.

PURPOSE: The present review is aimed to introduce an new occupational lung disease, Indium Lung. METHODS: We searched case reports and epidemiological studies concerning indium-related lung diseases and reviewed. RESULTS: Up to March, 2010, 7 cases of interstitial pneumonia in Japanese indium-exposed workers, two cases of pulmonary alveolar proteinosis (PAP) in US indium-exposed workers, one case of PAP in a Chinese indium-exposed worker, and 4 cross-sectional surveys in Japan had been published. All cases and epidemiological studies in Japan indicate that exposure to hardly soluble indium compounds causes interstitial as well as emphysematous lung damages, which we call "Indium Lung". Based on the epidemiological studies, the Japan Society for Occupational Health proposed 3 µg/l of indium in serum as an occupational exposure limit based on biological monitoring to prevent significant increase of KL-6. COMMENTS: Long-term follow-up of currently and formerly indium-exposed workers is essential not only to clarify the natural history of indium lung but also to trace the incidence of lung cancer. It is also necessary to elucidate the mechanism of indium lung and difference in clinical manifestations between Japanese and US cases.

Causal relationship between indium compound inhalation and effects on the lungs.

BACKGROUND: Recent case reports and epidemiological studies suggest that inhalation of indium dust induces lung damage. OBJECTIVES: To elucidate the dose-dependent effects of indium on the lungs and to prove a causal relationship more clearly. METHODS: A baseline observation was conducted on 465 workers currently exposed to indium, 127 workers formerly exposed to indium and 169 workers without indium exposure in 12 factories and 1 research laboratory from 2003 to 2006. Indium in serum (In-S) was determined as an exposure parameter, and its effects on the lungs were examined. RESULTS: The means of In-S in the current, former and no exposure workers were 8.35, 9.63 and 0.56 ng/ml, respectively. The current and former exposure workers had significantly higher levels of KL-6, and showed significant dose-dependent increases in KL-6, SP-D, and SP-A. Current exposure workers with In-S of 3 ng/ml or above demonstrated a significant increase of KL-6 in both GM and prevalence exceeding the reference value. Approximately a quarter of the former exposure workers had interstitial changes as seen on chest HRCT. In-S of exposed workers who had been working before improvements of the working environment (Group Bef) and those who started working after improvements (Group Aft) were 12.29 and 0.81 ng/ml, respectively. Adjusted odds ratios indicated 87%, 71% and 44% reductions among Group Aft workers who exceeded the reference values of KL-6, SP-D and SP-A, respectively. CONCLUSION: Dose-dependent lung effects due to indium exposure were shown, and a decrease of indium exposure reduced the lung effects. An In-S value of 3 ng/ml may be a cut-off value which could be used to prevent early effects on the lungs.

[Three cases of indium lung].

The production of indium tin oxide (ITO) has been increasing during the past decade because of its use in liquid crystal and plasma display panels. Following the first report on lethal lung injury in a ITO worker in 2001, we began pulmonary check-ups for 115 workers in the plant in our capacity of industrial physicians of the plant. Hence, we report interstitial pulmonary disease in 3 workers who had engaged in wet-surface grinding of ITO for 8 to 12 years and had significant lung injuries. The serum indium level and serum concentration of KL-6 were significantly elevated in all 3 cases. One non-smoker case among them showed severe obstructive changes on spirometry and had an episode of repeated bilateral pneumothorax before and during the follow-up period. All 3 cases showed both interstitial and/or emphysematous changes on HRCT. It is suggested that inhaled indium compounds can cause a new and unique interstitial pulmonary disease.