Transbronchial lung cryobiopsy: a novel confirmatory tool to diagnose asbestos-related pulmonary fibrosis

Our plain-English summary of Transbronchial lung cryobiopsy: a novel confirmatory tool to diagnose asbestos-related pulmonary fibrosis, by M. Zajaczkowska, A. Johnson, L. Gallur, et al (Respirology Case Reports, 2019).

The study

• Authors: M. Zajaczkowska, A. Johnson, L. Gallur, J. Shin, C. Henderson, J. Williamson
• Journal: Respirology Case Reports
• Published: 2019;7(1):e00380
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Asbestosis is diagnosed with a combination of historical, clinical and radiological findings in the absence of another cause. Histology is required when uncertainty exists, with lung biopsy via VATs being gold standard. Transbronchial cryobiopsy is becoming increasingly popular for diagnosing interstitial lung disease and may provide sufficient lung sample to demonstrate asbestosis. A 73 year old man presented with dyspnoea on a background of rheumatoid arthritis, previous methotrexate use and asbestos exposure. Examination revealed fine crackles in the mid and lower zones bilaterally without signs of pulmonary hypertension. The presence of pleural plaques and basal interstitial reticulation on HRCT was suggestive of asbestosis but histology was required to differentiate this from rheumatoid or methotrexate associated ILD. Samples of lung tissue were obtained via transbronchial cryobiopsy, demonstrating fibrosis and asbestos fibres consistent with asbestosis. Transbronchial cryobiopsy appears effective in obtaining sufficient parenchymal lung samples to diagnose asbestosis when clinical uncertainty exists.

In plain English

This Australian case report described a 73-year-old former smoker whose breathlessness on exertion had worsened over a few years. He reported heavy occupational asbestos exposure between ages 18 and 55, removing asbestos lagging from insulated pipes on ships. He also had rheumatoid arthritis and had previously taken methotrexate. Doctors considered these, and idiopathic pulmonary fibrosis, as other possible causes of lung scarring. Lung function tests showed a restrictive pattern, and CT showed calcified pleural plaques on both sides and increased markings at the lung bases. To distinguish them, doctors took lung tissue by transbronchial cryobiopsy, a freezing probe passed through the airways, without complications. The samples showed mild fibrosis and asbestos bodies: at least 14 per square centimetre in the right middle lobe, at least 9 in the right lower lobe. No biopsy features suggested connective tissue disease as the cause of the lung findings, and asbestosis was diagnosed from tissue, clinical and CT findings together. Electron microscopy was not performed. The authors concluded that cryobiopsy can yield samples large enough to show asbestos bodies in sufficient numbers.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 73-year-old man, a former smoker of 5 pack-years, with progressive exertional breathlessness, rheumatoid arthritis previously treated with methotrexate, type 2 diabetes, hypertension and obesity. The authors were at Liverpool Hospital, Sydney, Australia; no dates are given.
• Exposure: Heavy occupational asbestos exposure between ages 18 and 55, working on ships removing asbestos lagging from insulated pipes and rarely using protective breathing equipment. Fiber type was not determined.
• Main results:
  • Lung function tests showed a parenchymal restrictive process: TLC 72.2% predicted and DLCO 57.1% predicted.
  • High-resolution CT showed calcified pleural plaques on both sides, mainly in the lower zones, with increased subpleural reticular markings at the lung bases and no obvious honeycombing.
  • The cryobiopsy procedure was uncomplicated, and no pneumothorax was seen on the chest X-ray afterwards.
  • Bronchoalveolar lavage showed an isolated ferruginous body.
  • Two biopsies from the right middle lobe showed mild peribronchiolar fibrosis and multiple asbestos bodies, at a count of at least 14 per cm2.
  • Four biopsies from the right lower lobe also contained asbestos bodies, at least 9 per cm2.
  • The biopsies showed no significant interstitial inflammatory infiltrates, lymphoid aggregates, granulomas, vasculitis, haemorrhage or other specific features suggesting a connective tissue disease as the underlying cause of the lung pathology.
  • Based on the histopathology together with the clinical and radiological information, asbestosis was diagnosed.
• The authors' conclusion: The authors concluded that this case shows transbronchial cryobiopsy can obtain lung samples large enough to show asbestos bodies in sufficient numbers to confirm significant asbestos exposure and to indicate asbestos as the cause of pulmonary fibrosis. They suggested current guidelines could be modified to reflect advances in biopsy techniques.
• Limitations the authors state:
  • Electron microscopy, which can confirm that asbestos bodies contain asbestos fibres and identify fibre type, was not performed.
  • Asbestos bodies can also be formed by other substances, such as cellulose.
  • Studies directly comparing the diagnostic efficacy and safety of cryobiopsy and surgical biopsy in asbestosis are still needed.

Topics

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Histology, Biopsy, Video-Assisted Thoracoscopic Surgery (VATS), Interstitial Lung Disease, Asbestos Exposure, Pulmonary Hypertension, Pleural Plaques.

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