Cytological Diagnosis of Malignant Mesothelioma: A Case Series

Our plain-English summary of Cytological Diagnosis of Malignant Mesothelioma: A Case Series, by S. Dahiya, M. Singh, S. Jain, et al (Journal of Cytology, 2022).

The study

• Authors: S. Dahiya, M. Singh, S. Jain, B. Khuraijam, N. Suroya, S. Mandal
• Journal: Journal of Cytology
• Published: 2022;39(3):105-109
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Mesotheliomas are neoplasms of the serosal lining of the body cavities. Diagnosis requires a multimodal approach of clinical findings, cytology, and histopathology with immunohistochemistry (IHC). The published sensitivity of cytology for diagnosing mesothelioma ranges from 30% to 75%.

Aim And Objectives: This study aimed to calculate the incidence of malignant mesothelioma (MM) at our institute and to study the cytological features of MM.

Materials And Methods: A retrospective study of pleural, peritoneal, and pericardial fluids submitted at our institute was done. The duration of the study was 8 years (2011-2019). Apart from examining Giemsa smears, a panel of immunocytochemical (ICC) and cell block immunohistochemical (IHC) markers was applied to achieve the diagnosis. These included calretinin, mesothelin, CK5/6, Hector Battifora mesothelial cell antibody (HBME), WT1, MOC31, CK7 and CK20. Histopathological correlation was done wherever possible.

Result: In the present study, we compiled four cases of MM over 8 years diagnosed on serous effusion cytology and confirmed by immunocytochemistry (ICC)/cell block immunohistochemistry (IHC)/biopsy. This indicates a rare incidence of MM. The Cytological features of MM were studied.

Conclusion: The diagnosis of MM is difficult, especially cytologically. It was found to be a rare entity in the malignant cases diagnosed on effusion cytology.

Copyright: © 2022 Journal of Cytology.

In plain English

In this case series, pathologists in Delhi, India, reviewed 3,372 pleural, peritoneal and pericardial fluid samples submitted between January 2011 and October 2019. Twelve cases were suspected to be malignant mesothelioma on first screening. After further marker staining and, where possible, tissue examination, 4 of the 12 were confirmed as malignant mesothelioma. Of the other eight, seven were reactive (non-cancerous) mesothelial proliferations and one was adenocarcinoma. Three mesotheliomas were pleural and one peritoneal. The patients were aged 40 to 55, three men and one woman. One pleural case looked like adenocarcinoma on cytology and was identified as mesothelioma only after marker staining. The authors reported that cytology had a sensitivity of 75%, a specificity of 96%, and positive and negative predictive values of 27.2% and 99.4%. They calculated an incidence of 0.12%, which matches four cases among the 3,372 fluid samples at this institute; it is not a population rate. They stated that none of their cases were linked to asbestos exposure. The authors concluded that mesothelioma is rare in India and that fluid cytology can be a good first method of diagnosis.

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 drawn from a retro-prospective review of fluid samples at one institute
• Who was studied: 3,372 fluid samples (2,468 peritoneal, 732 pleural, 172 pericardial) submitted January 2011 to October 2019 to the Department of Pathology, Maulana Azad Medical College, Delhi, India. Only cases suspected to be mesothelioma were worked up further.
• Exposure: Asbestos exposure was not studied. The authors stated that none of their cases were linked to asbestos exposure. No fiber types are named.
• Main results:
  • 12 cases were suspected to be malignant mesothelioma on primary cytospin screening. 4 of these 12 were confirmed as malignant mesothelioma.
  • Of the remaining 8 suspected cases, 7 were reactive mesothelial proliferations and 1 was adenocarcinoma.
  • Case 4 (a 55-year-old man with pleural effusion) looked like adenocarcinoma on primary screening but was found to be mesothelioma after marker staining.
  • Cytological examination: sensitivity 75%, specificity 96%, positive predictive value 27.2%, negative predictive value 99.4%.
  • With four cases diagnosed, the overall incidence was calculated as 0.12%. This matches 4 cases among the 3,372 fluid samples submitted to this institute. It is not a population incidence.
  • Three cases were pleural: total incidence 0.4%, and 3.3% of malignant pleural cases.
  • One case was peritoneal, giving 0.9% of malignant peritoneal cases (total incidence 0.04%).
  • The patients with mesothelioma were aged 40 to 55 years, with a male to female ratio of 3 to 1.
  • Cases 1, 2 and 3 showed atypical mesothelial cells in three-dimensional clusters and balls with scalloped edges.
• The authors' conclusion: The authors concluded that malignant mesothelioma is rare in India. They concluded that, although a multimodal approach is needed, cytology can be a good primary and effective method for a pathological diagnosis of mesothelioma.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Neoplasm, Cytology, Histopathology, Immunohistochemistry, Pericardial, Cell Block, Calretinin.

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