Outcome of patients with nonspecific pleuritis at thoracoscopy

Our plain-English summary of Outcome of patients with nonspecific pleuritis at thoracoscopy, by J.M. Wrightson, H.E. Davies (Current Opinion in Pulmonary Medicine, 2011).

The study

• Authors: J.M. Wrightson, H.E. Davies
• Journal: Current Opinion in Pulmonary Medicine
• Published: 2011;17(4):242-6
• Type of article: Review
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose Of Review: The histological finding of pleural inflammation (pleuritis/fibrosis) is frequently found in pleural biopsies taken at thoracoscopy. This is a nonspecific finding, representing a common endpoint of many pleural conditions. Additional features, such as malignant cells, caseating granulomas and evidence of vasculitis, are required to make an aetiological histological diagnosis; in the absence of these features, the term 'nonspecific pleuritis/fibrosis' (NSP) is used. The cause of NSP is obscure and presents a particular dilemma: whether this apparently benign result represents a 'false-negative' sampling error in malignancy.

Recent Findings: In a recent longitudinal follow-up study of 142 patients undergoing thoracoscopy, NSP was found in 31%. Of these, a likely cause for the NSP was found in 38% and malignancy occurred in 12%. These data were consistent with previous studies.

Summary: NSP is a histological diagnosis made in approximately 30-40% of patients with an undiagnosed exudative pleural effusion. The majority of cases adopt a benign course, although 8-12% may be subsequently found to have malignancy, particularly mesothelioma. In 25-91% no cause for the NSP is found; these patients are considered to have 'idiopathic pleuritis'. Prolonged follow-up, with occasionally further (usually more invasive) biopsies, is essential to rule out malignancy.

In plain English

This article was a review, not a new study. The authors reviewed published research on patients whose pleural biopsies, mostly taken at thoracoscopy, showed 'nonspecific pleuritis/fibrosis' (NSP): inflammation or scarring of the pleura with no features pointing to a particular cause. They gave most attention to a 2010 study by Davies and colleagues of 142 patients with undiagnosed exudative pleural effusion, in which 31% had NSP. The 44 NSP patients were followed for a mean of 21.3 months. A likely cause was found in 38% of them. 12% (5 patients) were later diagnosed with malignancy, and each of these had mesothelioma. In 62%, no cause was found, which is called 'idiopathic pleuritis'. That study did not find a relationship between prior asbestos exposure and a missed malignancy, in contrast to an increased risk reported in another study by Venekamp and colleagues. Across the reviewed thoracoscopy studies, malignancy was later found in 0 to 12% of NSP patients. The authors concluded that about 10% of NSP patients have an underlying malignancy, often mesothelioma, and advocated follow-up of at least 2 years.

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: Narrative review of published studies
• Who was studied: Published studies of patients whose pleural biopsies (thoracoscopy, thoracotomy or closed needle biopsy) showed nonspecific pleuritis/fibrosis. The table lists eight studies from 1981 to 2010, centred on a 2010 study of 142 patients undergoing medical thoracoscopy for undiagnosed exudative pleural effusion.
• Exposure: No specific exposure was studied. Asbestos exposure was mentioned as a risk factor for malignancy, and the reviewed studies examined it as a possible predictor of a false-negative (missed malignancy) NSP biopsy.
• Main results:
  • In the Davies et al. study, 31% of the 142 patients who underwent thoracoscopy had a histological diagnosis of NSP.
  • In the Davies et al. study, 38% of the patients with NSP had a likely cause found after follow-up (mean 21.3 months).
  • In the Davies et al. study, 12% of NSP patients (5 patients) were diagnosed with malignancy, and their initial biopsies were considered false negative.
  • In the Davies et al. study, each of the 5 patients with a missed malignancy had mesothelioma.
  • In the Davies et al. study, 62% of NSP patients had no likely cause for their effusion found, despite follow-up over a mean of 19.6 months (idiopathic pleuritis).
  • The Davies et al. study did not find a relationship between prior asbestos exposure and a false-negative NSP diagnosis.
  • Venekamp et al. had reported an increased risk of a false-negative NSP diagnosis with asbestos exposure, in contrast to the Davies et al. finding.
  • In the Davies et al. study, false-negative results were more common in patients with prethoracoscopy suspicion of malignancy, pleural nodules or plaques at thoracoscopy, or fluid recurrence, but these associations were not statistically significant.
  • Across studies of thoracoscopic biopsies, malignancy was found in 0 to 12% of patients with an initial diagnosis of NSP.
  • In Janssen et al.'s retrospective analysis of 709 thoracoscopies, 8% of patients (31/391) with an initial diagnosis of 'nonmalignant pleuritis' developed malignancy. Mesothelioma was the most common (10/31).
  • In Venekamp et al.'s study of 60 NSP patients, a similar proportion of those with a probable benign cause and those with idiopathic NSP developed malignancy (4/46 vs. 1/14).
• The authors' conclusion: The authors concluded that NSP is a common thoracoscopic biopsy finding, that about 10% of these patients have an underlying malignancy, often mesothelioma, and they advocated follow-up of at least 2 years for those with NSP and no concerning clinical features.
• Limitations the authors state:
  • The authors noted that the NSP frequency from the Janssen et al. study is likely overstated, because that study counted all 'nonmalignant pleuritis' (including tuberculosis) rather than NSP alone.

Topics

Medical terms in this study, explained in our Lexicon: Thoracoscopy, Inflammation, Fibrosis, Granuloma, Pleural Effusion, Mesothelioma, Idiopathic.

Related studies

• Outcome of patients diagnosed with fibrinous pleuritis after medical thoracoscopy — M. Metintas, G. Ak, et al. (2012)
• Outcome of patients with nonspecific pleuritis/fibrosis on thoracoscopic pleural biopsies — H.E. Davies, J.E. Nicholson, et al. (2010)
• What is the significance of non-specific pleuritis? A trick question — J. Janssen, F. Maldonado, et al. (2018)
• Diagnostic accuracy and safety of semirigid thoracoscopy in exudative pleural effusions in Denmark — F. Willendrup, U. Bodtger, et al. (2014)
• Nonspecific pleuritis: optimal duration of follow-up — Z.S. DePew, A. Verma, et al. (2014)
• Chronic follicular pleuritis: a B cell-rich form of nonspecific pleuritis/fibrosis — S.A. Yousem (2019)

Browse more research in Current Opinion in Pulmonary Medicine, or return to medical research.