Giant cell interstitial pneumonia in patients without hard metal exposure: analysis of 3 cases and review of the literature

Unusual hard metal lung disease: bronchiolocentric interstitial pneumonia

A 38-year-old woman experienced a persistent dry cough and progressively worsening dyspnoea for 2 years. Spirometry testing revealed a moderate-to-severe restrictive abnormality. High-resolution chest computed tomography showed diffuse reticulonodular opacities. A lung biopsy disclosed alveolar parenchymal inflammation and fibrosis with bronchiolocentric features, prompting consideration of interstitial pneumonia. Following a thorough investigation of her occupational history and an on-site inspection, it was discovered that the patient had been grinding drill bits designed for printed circuit boards for 8 years, exposing her to hard metals. Mineralogical analyses confirmed excessive tungsten in urine, serum and hair, leading to a diagnosis of hard metal lung disease due to tungsten carbide-cobalt exposure. After discontinuing exposure and commencing corticosteroid therapy, her symptoms, pulmonary function and imaging showed modest improvement. This case highlights the significance of assessing occupational history in patients with interstitial pneumonia and understanding industrial hazards for accurate diagnosis and care.

Pulmonary dust foci as rat pneumoconiosis lesion induced by titanium dioxide nanoparticles in 13-week inhalation study

Background

Most toxicological studies on titanium dioxide (TiO₂) particles to date have concentrated on carcinogenicity and acute toxicity, with few studies focusing of pneumoconiosis, which is a variety of airspace and interstitial lung diseases caused by particle-laden macrophages. The present study examined rat pulmonary lesions associated with pneumoconiosis after inhalation exposure to TiO₂ nanoparticles (NPs).

Methods

Male and female F344 rats were exposed to 6.3, 12.5, 25, or 50 mg/m³ anatase type TiO₂ NPs for 6 h/day, 5 days/week for 13 weeks using a whole-body inhalation exposure system. After the last exposure the rats were euthanized and blood, bronchoalveolar lavage fluid, and all tissues including lungs and mediastinal lymph nodes were collected and subjected to biological and histopathological analyses.

Results

Numerous milky white spots were present in the lungs after exposure to 25 and 50 mg/m³ TiO₂ NPs. Histopathological analysis revealed that the spots were alveolar lesions, characterized predominantly by the agglomeration of particle-laden macrophages and the presence of reactive alveolar epithelial type 2 cell (AEC2) hyperplasia. We defined this characteristic lesion as pulmonary dust foci (PDF). The PDF is an inflammatory niche, with decreased vascular endothelial cells in the interstitium, and proliferating AEC2 transformed into alveolar epithelial progenitor cells. In the present study, the AEC2 in the PDF had acquired DNA damage. Based on PDF induction, the lowest observed adverse effect concentration for pulmonary disorders in male and female rats was 12.5 mg/m³ and 6.3 mg/m³, respectively. The no observed adverse effect concentration for male rats was 6.3 mg/m³. There was a sex difference in lung lesion development, with females showing more pronounced lesion parameters than males.

Conclusions

Inhalation exposure to TiO₂ NPs caused PDF, an air-space lesion which is an alveolar inflammatory niche containing particle-laden macrophages and proliferating AEC2. These PDFs histopathologically resemble some pneumoconiosis lesions (pulmonary siderosis and hard metal pneumoconiosis) in workers and lung disease in smokers, suggesting that PDFs caused by exposure to TiO₂ NPs in rats are an early pneumoconiosis lesion and may be a common alveolar reaction in mammals.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00498-3.

Giant Cell Interstitial Pneumonia In Native, Transplanted And Re-Transplanted Lungs 8 Years Apart Without Known Hard Metal Exposure

Pneumoconioses are a group of non-neoplastic pulmonary disorders caused by inhaled inorganic particles. Well-described pneumoconioses include asbestosis, silicosis, coal worker's pneumoconiosis, chronic beryllium disease, and hard metal lung disease. Giant cell interstitial pneumonia (GIP) is a distinctive and rare pneumoconiosis most frequently found in workers exposed to hard metals, primarily cobalt and tungsten carbide. The pathologic picture is considered virtually pathognomonic for hard metal lung disease, although this dogma has been questioned by a few reports of giant cell interstitial pneumonia in patients without apparent hard metal exposure. Giant cell interstitial pneumonia is even rarer in lung transplant recipients. Here, we present a patient without known hard metal exposure who was found to have persistent giant cell interstitial pneumonia in native, transplanted and re-transplanted lungs 8 years apart.

Pulmonary toxicity, genotoxicity, and carcinogenicity evaluation of molybdenum, lithium, and tungsten: A review

Molybdenum, lithium, and tungsten are constituents of many products, and exposure to these elements potentially occurs at work. Therefore it is important to determine at what levels they are toxic, and thus we set out to review their pulmonary toxicity, genotoxicity, and carcinogenicity. After pulmonary exposure, molybdenum and tungsten are increased in multiple tissues; data on the distribution of lithium are limited. Excretion of all three elements is both via faeces and urine. Molybdenum trioxide exerted pulmonary toxicity in a 2-year inhalation study in rats and mice with a lowest-observed-adverse-effect concentration (LOAEC) of 6.6 mg Mo/m³. Lithium chloride had a LOAEC of 1.9 mg Li/m³ after subacute inhalation in rabbits. Tungsten oxide nanoparticles resulted in a no-observed-adverse-effect concentration (NOAEC) of 5 mg/m³ after inhalation in hamsters. In another study, tungsten blue oxide had a LOAEC of 63 mg W/m³ in rats. Concerning genotoxicity, for molybdenum, the in vivo genotoxicity after inhalation remains unknown; however, there was some evidence of carcinogenicity of molybdenum trioxide. The data on the genotoxicity of lithium are equivocal, and one carcinogenicity study was negative. Tungsten seems to have a genotoxic potential, but the data on carcinogenicity are equivocal. In conclusion, for all three elements, dose descriptors for inhalation toxicity were identified, and the potential for genotoxicity and carcinogenicity was assessed.

Imaging diagnosis of classical and new pneumoconiosis: predominant reticular HRCT pattern

Our understanding of the manifestations of pneumoconioses is evolving in recent years. Associations between novel exposures and diffuse interstitial lung disease have been newly recognized. In advanced asbestosis, two types of fibrosis are seen, probably related to dose of exposure, existence of pleural fibrosis, and the host factor status of the individual. In pneumoconiosis of predominant reticular type, nodular opacities are often seen in the early phase. The nodular pattern is centrilobular, although some in metal lung show perilymphatic distribution, mimicking sarcoidosis. High-resolution computed tomography enables a more comprehensive correlation between the pathologic findings and clinically relevant imaging findings. The clinician must understand the spectrum of characteristic imaging features related to both known dust exposures and to historically recent new dust exposures.

The relationship between respiratory health and hard metal dust exposure: A cross-sectional study

The frequency and severity of respiratory disorders among workers exposed to hard metal dust is not well known.The objective of this cross-sectional study is to report the prevalence of respiratory symptoms, functional status, and radiological findings in hard metal-exposed workers in Türkiye.Among 139 workers, 96 were machining workers, and 43 were industrial tool sharpening workers. Radiographic abnormalities compatible with pneumoconiosis were found 39% of the workers and were more in machining workers statistically significant.Also, in machining workers group, percentage of expected values of FVC was lower than industrial tool sharpening workers group. The prevalence of respiratory symptoms was 14.3%, and there was not a statistically significant difference in working groups. The study reveals that pulmonary symptoms, functional abnormalities, and radiological findings are mild. Assuming that reversibility may develop with avoidance from exposure when detected at this stage, early diagnosis of lung damage is essential.

Unusual pneumoconiosis in two patients with heavy print toner, and paper dust exposure

Workers in a print shop are exposed to photocopier toner dust and paper dust over a prolonged period of time. However, there are only rare case reports of toner and paper dust induced lung damage in humans. We reviewed our consultation files for a period of 30 years from 1987 to 2018 to look for cases with a diagnosis of giant cell interstitial pneumonia (GIP), printer toner exposure and paper dust exposure resulting in lung disease. There were two cases which met our inclusion criteria. Slides, clinical histories and imaging were reviewed. Both the patients had worked in print shops, and had no history of exposure to hard metals. Patient 1 presented with shortness of breath and cough over several months, while patient 2 was asymptomatic at presentation. Both the patients underwent surgical lung biopsies. Histopathologic examination from both the cases showed a spectrum of pathology, including features of GIP, desquamative interstitial pneumonia, chronic bronchiolitis with lymphoid hyperplasia, and particulate matter consistent with toner. Energy dispersive spectroscopy was performed on one case, and it revealed no cobalt or tungsten particles. The unusual combination of findings is very suggestive that toner particles with or without paper dust exposure were responsible for the pathologic changes in the lungs of these patients. This possibility should be explored further with additional patients who work in print shops where they are exposed to paper dust and paper toner and have signs or symptoms of diffuse lung disease.

Hard metal lung disease: a case series

Objective:

To describe diagnostic and treatment aspects of hard metal lung disease (HMLD) and to review the current literature on the topic.

Methods:

This was a retrospective study based on the medical records of patients treated at the Occupational Respiratory Diseases Clinic of the Instituto do Coração, in the city of São Paulo, Brazil, between 2010 and 2013.

Results:

Of 320 patients treated during the study period, 5 (1.56%) were diagnosed with HMLD. All of those 5 patients were male (mean age, 42.0 ± 13.6 years; mean duration of exposure to hard metals, 11.4 ± 8.0 years). Occupational histories were taken, after which the patients underwent clinical evaluation, chest HRCT, pulmonary function tests, bronchoscopy, BAL, and lung biopsy. Restrictive lung disease was found in all subjects. The most common chest HRCT finding was ground glass opacities (in 80%). In 4 patients, BALF revealed multinucleated giant cells. In 3 patients, lung biopsy revealed giant cell interstitial pneumonia. One patient was diagnosed with desquamative interstitial pneumonia associated with cellular bronchiolitis, and another was diagnosed with a hypersensitivity pneumonitis pattern. All patients were withdrawn from exposure and treated with corticosteroid. Clinical improvement occurred in 2 patients, whereas the disease progressed in 3.

Conclusions:

Although HMLD is a rare entity, it should always be included in the differential diagnosis of respiratory dysfunction in workers with a high occupational risk of exposure to hard metal particles. A relevant history (clinical and occupational) accompanied by chest HRCT and BAL findings suggestive of the disease might be sufficient for the diagnosis.

Objetivo:

Descrever aspectos relacionados ao diagnóstico e tratamento de pacientes com doença pulmonar por metal duro (DPMD) e realizar uma revisão da literatura.

Métodos:

Estudo retrospectivo dos prontuários médicos de pacientes atendidos no Serviço de Doenças Respiratórias Ocupacionais do Instituto do Coração, localizado na cidade de São Paulo, entre 2010 e 2013.

Resultados:

Entre 320 pacientes atendidos no período do estudo, 5 (1,56%) foram diagnosticados com DPMD. Todos os pacientes eram do sexo masculino, com média de idade de 42,0 ± 13,6 anos e média de tempo de exposição a metal duro de 11,4 ± 8,0 anos. Os pacientes foram submetidos a avaliação clinica, história ocupacional, TCAR de tórax, prova de função pulmonar, broncoscopia com LBA e biópsia pulmonar. Todos apresentaram distúrbio ventilatório restritivo. O achado de imagem à TCAR de tórax mais frequente foi de opacidades em vidro fosco (em 80%). Em 4 pacientes, o LBA revelou presença de células gigantes multinucleadas. Em 3, foi diagnosticada pneumonia intersticial por células gigantes na biópsia pulmonar. Houve o diagnóstico de pneumonia intersticial descamativa associada à bronquiolite celular em 1 paciente e de pneumonite de hipersensibilidade em 1. Todos foram afastados da exposição e tratados com corticoide. Houve melhora em 2 pacientes e progressão da doença em 3.

Conclusões:

Apesar de ser uma entidade rara, a DPMD deve ser sempre considerada em trabalhadores com risco ocupacional elevado de exposição a metais duros. A história clínica e ocupacional associada a achados em TCAR de tórax e LBA sugestivos da doença podem ser suficientes para o diagnóstico.

Cobalt related interstitial lung disease

Cobalt exposure in the hard metal and bonded diamond tool industry is a well-established cause of ILD. The primary theories regarding the underlying mechanism of cobalt related ILD include an immunologic mechanism and an oxidant injury mechanism. Cobalt related ILD may present in subacute and chronic forms and often has associated upper respiratory symptoms. The evaluation begins with a thorough occupational history and includes PFTs, HRCT, and bronchoalveolar lavage. HRCT findings are nonspecific and may resemble NSIP, UIP, sarcoidosis, or HP. The finding of cannibalistic multinucleated giant cells is diagnostic provided there is a history of exposure and appropriate changes on imaging; however, when these cells are not found on lavage, lung biopsy is required for diagnosis. Giant cell interstitial pneumonia is the classic pathologic pattern, but cobalt related ILD may also present with pathologic findings of UIP, DIP, or HP. When cobalt related ILD is suspected, removal from exposure is the most important step in treatment. Case reports suggest that treatment with steroids results in symptomatic, physiologic, and radiographic improvement.