Chronic follicular pleuritis: a B cell-rich form of nonspecific pleuritis/fibrosis

Our plain-English summary of Chronic follicular pleuritis: a B cell-rich form of nonspecific pleuritis/fibrosis, by S.A. Yousem (Human Pathology, 2019).

The study

• Author: S.A. Yousem
• Journal: Human Pathology
• Published: 2019;90:14-19
• Read it: PubMed · Publisher

Abstract

The parietal pleura is often biopsied in patients with idiopathic pleural effusion, and in up to 40% of cases, a diagnosis of nonspecific pleuritis/fibrosis (NSP) is rendered. The histology of this reaction has not been well described including a pattern of B cell lymphoid hyperplasia described as "chronic follicular pleuritis (CFP)". Thirty-two cases of NSP were studied, of which 13 (41%) corresponded to CFP with the remainder displaying a fibrinous and organizing pleuritis with varying degrees of collagenization. CFP had similar etiologies as NSP with long term follow-up, including cardiac disease, pericarditis, asbestos exposure, and occult malignancy. The importance of recognizing a previously undescribed B cell/plasma cell pleural inflammatory response in reactive pleural disease is discussed.

Copyright © 2019 Elsevier Inc. All rights reserved.

In plain English

The author reviewed 32 parietal pleural biopsies from patients with unexplained (idiopathic) pleural effusion. The biopsies came from University of Pittsburgh Medical Center pathology files for 2003 to 2018, and none had shown cancer or infection. Thirteen (41%) showed a pattern the author named chronic follicular pleuritis, in which the inflammation was largely B cells, with no clonal cell population in the 6 cases tested. The other 19 showed nonspecific pleuritis/fibrosis. Two patients in each group had a history of asbestos exposure; the article does not name fiber types. On follow-up, a cause was found in 11 of the 19 nonspecific cases, including asbestos pleuritis in 1. A cause was also found in 7 of the 13 follicular cases (the discussion says 6), including asbestos pleuritis in 1. Three follicular cases showed hyaline pleural plaques, and none showed malignant mesothelioma. The author concluded that chronic follicular pleuritis is a distinct form of nonspecific pleuritis that can be confused with malignant lymphoma. The author noted the limits of a retrospective study.

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: Retrospective case series: review of pathology slides and medical records from one institution
• Who was studied: 32 patients with idiopathic pleural effusion and parietal pleural biopsies showing nonspecific pleuritis, from University of Pittsburgh Medical Center pathology files, 2003 to 2018. Of these, 19 had nonspecific pleuritis/fibrosis (11 men, 8 women, average age 60.5 years). The other 13 had chronic follicular pleuritis, mainly elderly men (mean age 69.3 years).
• Exposure: Asbestos was not the main subject of the study. A history of asbestos exposure was recorded in 2 of the 19 nonspecific pleuritis/fibrosis patients and in 2 of the 13 chronic follicular pleuritis patients. No fiber types or doses are given.
• Main results:
  • 13 of the 32 cases (41%) showed chronic follicular pleuritis.
  • In the chronic follicular pleuritis cases, the lymphoid aggregates were largely B cells. Gene rearrangement studies found no clonal B or T cell population in 6 cases.
  • In the 19 nonspecific pleuritis/fibrosis patients, follow-up identified a cause in 11 cases, including metastatic adenocarcinoma in 2 and asbestos pleuritis in 1. Eight cases were considered idiopathic.
  • In the 13 chronic follicular pleuritis patients, a cause was identified in 7 (54%): constrictive pericarditis (2), metastatic lung adenocarcinoma (2), chronic congestive heart failure or Dressler's syndrome (2), and asbestos pleuritis (1). Six cases (46%) were idiopathic.
  • Hyaline pleural plaques were present in 3 of the 13 chronic follicular pleuritis cases (23%).
  • None of the chronic follicular pleuritis cases showed malignant mesothelioma or malignant lymphoma.
  • Pleural fluid came back and needed draining in 3 of the 13 chronic follicular pleuritis cases (23%). In the nonspecific pleuritis/fibrosis group, 4 of 19 patients (21%) had recurrent disease.
  • The author had expected chronic follicular pleuritis to be associated with autoimmune disease or allergic phenomena, but this association was not found.
• The authors' conclusion: The author concluded that chronic follicular pleuritis is a B cell-rich, distinct form of idiopathic nonspecific pleuritis that can be confused with malignant lymphoma. In the author's view, its causes resemble those of nonspecific pleuritis.
• Limitations the authors state:
  • The study was retrospective.
  • Pleural fluid was not tested by flow cytometry for cell typing in any case.
  • Gram and acid-fast stains were not done in every case.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Fibrosis, Parietal Pleura, Idiopathic, Pleural Effusion, Histology, Asbestos Exposure.

Related studies

• Outcome of patients with nonspecific pleuritis/fibrosis on thoracoscopic pleural biopsies — H.E. Davies, J.E. Nicholson, et al. (2010)
• Nonspecific pleuritis: optimal duration of follow-up — Z.S. DePew, A. Verma, et al. (2014)
• Outcome of patients with nonspecific pleuritis at thoracoscopy — J.M. Wrightson, H.E. Davies (2011)
• How useful is GLUT-1 in differentiating mesothelial hyperplasia and fibrosing pleuritis from epithelioid and sarcomatoid mesotheliomas? An international collaborative study — A.N. Husain, M.K. Mirza, et al. (2014)
• Mesothelial cell proliferation: a nonspecific response to lung injury associated with fibrosis — I.Y. Adamson, J. Bakowska, et al. (1994)
• Sonography of the pleura — J. Reuss (2010)

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