Malignant pleural mesothelioma in situ

Our plain-English summary of Malignant pleural mesothelioma in situ, by K. Ando, T. Morohoshi, Y. Tsuura, et al (Interactive Cardiovascular and Thoracic Surgery, 2022).

The study

• Authors: K. Ando, T. Morohoshi, Y. Tsuura, M. Masuda
• Journal: Interactive Cardiovascular and Thoracic Surgery
• Published: 2022;35(5)
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Although the diagnosis of malignant pleural mesothelioma at an in situ stage was traditionally challenging, it is now possible owing to advances in molecular biological methods such as P16 fluorescence in situ hybridization or BRCA1-associated protein 1 immunohistochemistry. Here, we report the first case, to our knowledge, of total parietal pleurectomy for mesothelioma in situ. Future follow-up and accumulation of cases are necessary to determine whether total parietal pleurectomy could be applied as a treatment for mesothelioma in situ or not.

© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.

In plain English

This case report describes one patient in Japan: a 71-year-old man exposed to asbestos while working at a shipyard. No fiber type is named. He had shortness of breath and fluid around the right lung. Cells from the fluid suggested malignant pleural mesothelioma, and a genetic test (FISH) found a homozygous deletion of the P16 gene in 52% of the cells. The authors wrote that mesothelioma could not be diagnosed at the time. A CT scan showed no nodules, and a thoracoscopic biopsy found no mesothelioma. Surgeons then removed the whole parietal pleura, including the diaphragmatic and mediastinal pleura, but not the visceral pleura covering the lung. No tumour invasion into fatty (adipose) tissue was found. Based on more recent reports, the authors revised the diagnosis to mesothelioma in situ, an early stage before invasion. Five years after surgery, CT showed no recurrence. Because the visceral pleura was left in place, the authors said remaining mesothelioma could not be ruled out. They concluded that more follow-up and more cases are needed to judge this surgery as a treatment.

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 (one patient)
• Who was studied: one 71-year-old man treated at Yokosuka Kyosai Hospital, Japan; the operation took place five years before the report
• Exposure: asbestos exposure while working at a shipyard; no fiber type or dose given
• Main results:
  • FISH found a homozygous deletion of the P16 gene in 52% of the cells from the patient's pleural fluid cell block
  • Despite this, the authors state mesothelioma could not be diagnosed at that time
  • Contrast-enhanced CT showed slight pleural effusion and mild pleural thickening but no nodules
  • At thoracoscopy, pleural plaques were seen but no visible mesothelioma, and the biopsy showed no invasive mesothelioma
  • Total parietal pleurectomy, including the diaphragmatic and mediastinal pleura, was performed; the visceral pleura was not removed
  • No tumour invasion into the adipose tissue was found in the removed specimen
  • The diagnosis was revised to mesothelioma in situ based on later reports; BAP1 loss was not observed
  • Five years after the operation, CT follow-up showed no recurrence in this patient
• The authors' conclusion: The authors concluded that further follow-up and more cases are needed to determine whether total parietal pleurectomy is a useful treatment for mesothelioma in situ
• Limitations the authors state:
  • Because the visceral pleura was not removed, the authors could not rule out that mesothelioma remains

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Fluorescence In Situ Hybridization (FISH), Immunohistochemistry, Mesothelioma in Situ.

Related studies

• MTAP immunohistochemistry is an accurate and reproducible surrogate for CDKN2A fluorescence in situ hybridization in diagnosis of malignant pleural mesothelioma — D.B. Chapel, J.J. Schulte, et al. (2020)
• Utility of Methylthioadenosine Phosphorylase Compared With BAP1 Immunohistochemistry, and CDKN2A and NF2 Fluorescence In Situ Hybridization in Separating Reactive Mesothelial Proliferations From Epithelioid Malignant Mesotheliomas — K.B. Berg, S. Dacic, et al. (2018)
• Fluorescence in situ hybridization in the definitive diagnosis of malignant mesothelioma in effusion cytology — S. Savic, N. Franco, et al. (2010)
• 9p21 deletion in the diagnosis of malignant mesothelioma, using fluorescence in situ hybridization analysis — M. Takeda, T. Kasai, et al. (2010)
• Adaptation of a commercial fluorescent in situ hybridization test to the diagnosis of malignant cells in effusions — C. Flores-Staino, E. Darai-Ramqvist, et al. (2010)
• BAP1 immunohistochemistry has limited prognostic utility as a complement of CDKN2A (p16) fluorescence in situ hybridization in malignant pleural mesothelioma — S.M. McGregor, J. McElherne, et al. (2017)

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