Well-differentiated papillary mesothelioma of the pleura: a series of 24 cases

Our plain-English summary of Well-differentiated papillary mesothelioma of the pleura: a series of 24 cases, by F. Galateau-Sallé, J.M. Vignaud, L. Burke, et al (The American Journal of Surgical Pathology, 2004).

The study

• Authors: F. Galateau-Sallé, J.M. Vignaud, L. Burke, A. Gibbs, E. Brambilla, R. Attanoos, M. Goldberg, G. Launoy, Mesopath group
• Journal: The American Journal of Surgical Pathology
• Published: 2004;28(4):534-40
• Cited by: 78 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Well-differentiated papillary mesothelioma (WDPM) of the pleura represents a distinct mesothelial tumor presenting with unilateral pleural effusion and superficial spreading of stout papillary formations with myxoid cores, lined by bland, flattened, or epithelioid cells, without or with limited invasion of the submesothelial layer. The majority of cases have been reported in the peritoneum in women of reproductive age with no history of asbestos exposure and also in the tunica vaginalis of men. We report 24 cases of pleural WDPM and compared their histologic, epidemiologic, and clinical features with those of classic mesothelioma. Men and women were equally affected, with a mean age of 60 years. Half of the patients had a history of occupational asbestos exposure. In 11 patients with a minimal follow-up period of 24 months, the survival ranged from 36 to 180 months with an average of 74 months as compared with 9.89 months for 1248 paired patients with diffuse malignant mesothelioma. Ten-year survival was 30.8%. We conclude that WDPM is a rare and unusual mesothelial tumor, characterized by a lack of deep invasion and associated with an indolent clinical course and long survival. For these reasons, WDPM is best considered as a specific clinico-pathologic entity distinct from conventional diffuse malignant mesothelioma.

In plain English

This study described 24 cases of well-differentiated papillary mesothelioma (WDPM) of the pleura, a rare mesothelial tumor, collected from French and Cardiff pathology groups. The patients were 11 men and 13 women aged 31 to 79. A history of asbestos exposure was found in 11 of the 24 (45.8%). Most of these exposures were occupational, and 2 came through household contact. Nine patients had no history of exposure. The article did not report fiber types. Most patients had breathlessness and recurring fluid around the lung, without chest pain. Invasion, seen in 10 cases, was limited to the layers just beneath the surface lining. Among 11 patients followed at least 24 months, survival ranged from 36 to 180 months (average 74), compared with 9.89 months for 1248 paired patients with diffuse malignant mesothelioma. Ten-year survival was 30.8%. The authors concluded that WDPM should be considered an entity distinct from diffuse malignant mesothelioma. They said its possible link with asbestos needs further study, because the high share of exposed patients could reflect either a true association or a gender or selection bias.

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 series: cases identified from pathology panel files, with clinical, histologic and immunohistochemical review
• Who was studied: 24 patients with WDPM of the pleura: 21 from the French Mesothelioma Panel (Mesopath group) and 3 from the Environmental Lung Disease Research Group, Cardiff. There were 11 men and 13 women aged 31 to 79 years (average 60). Study dates were not stated.
• Exposure: History of asbestos exposure, mostly occupational, with 2 cases through household (para-occupational) contact. Jobs listed in the case table include metal-worker, shipyard engineer, garage hand, clothing industry worker and gunpowder factory worker. Fiber types and doses were not reported.
• Main results:
  • 11 of the 24 patients (45.8%) had a history of asbestos exposure.
  • 9 patients had no history of asbestos exposure.
  • Among 11 patients with at least 24 months of follow-up, survival ranged from 36 to 180 months, averaging 74 months. This compared with 9.89 months for 1248 paired patients with diffuse malignant mesothelioma.
  • Ten-year survival was 30.8%.
  • Seventeen patients were alive with disease at the time of reporting.
  • Two patients with no invasion on the first biopsy had a 10-year symptom-free interval before the disease spread and they died.
  • Invasion was present in 10 cases at diagnosis but was strictly limited to the submesothelial layers.
  • In 2 cases, the tumor looked like a conventional epithelioid mesothelioma under the microscope when the disease progressed.
  • Pleural plaques were seen under the microscope in 1 case but were not detected on imaging.
  • Most patients presented with breathlessness (dyspnea) and recurrent pleural effusion without chest pain.
• The authors' conclusion: The authors concluded that WDPM is a rare, unusual mesothelial tumor marked by lack of deep invasion, a slow (indolent) course and long survival, and that it is best considered a distinct entity from conventional diffuse malignant mesothelioma. They wrote that survival did not appear to be improved by chemotherapy or radiotherapy, and that the suggested link between pleural WDPM and asbestos exposure needs further study.
• Limitations the authors state:
  • The authors stated that the high proportion of asbestos-exposed patients could reflect a true association or a gender or selection bias.
  • Not enough tissue was available to assess p53 except in 7 cases.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Well-Differentiated Papillary Mesothelioma, Pleura, Pleural Effusion, Epithelioid, Peritoneum, Asbestos Exposure, Tunica Vaginalis, Mesothelioma.

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