Diagnostic efficacy of electron microscopy and pleural effusion cytology for the distinction of pleural mesothelioma and lung adenocarcinoma

Our plain-English summary of Diagnostic efficacy of electron microscopy and pleural effusion cytology for the distinction of pleural mesothelioma and lung adenocarcinoma, by H. Domínguez-Malagón, A.M. Cano-Valdez, C. González-Carrillo, et al (Ultrastructural Pathology, 2016).

The study

• Authors: H. Domínguez-Malagón, A.M. Cano-Valdez, C. González-Carrillo, Y.E. Campos-Salgado, A. Lara-Garcia, M. Lopez-Mejia, J.F. Corona-Cruz, O. Arrieta
• Journal: Ultrastructural Pathology
• Published: 2016;40(5):254-60
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The diagnosis of malignant pleural mesothelioma (MPM) is challenging and requires immunohistochemistry or electron microscopy assays to specifically differentiate MPM from lung adenocarcinoma. An ultrastructural study of fresh tissue is considered to be the "gold standard." In most cases, the first diagnostic approach is performed on pleural effusion, and in some patients, this is the only available sample for diagnosis. The aim of the present study is to evaluate if an examination of pleural effusion samples based on electron microscopy (EMpe) is a useful tool for the differential diagnosis of MPM and lung adenocarcinoma. An EMpe study was performed in 25 pleural effusion samples. Histological and immunohistochemical markers confirmed the diagnosis of either mesothelioma (5) or adenocarcinoma (20). Of the five cases that were diagnosed with mesothelioma, two samples (40%) showed cells with "bushy" microvilli, which are characteristic of mesothelioma, by EMpe, and three were acellular (60%). Of the 20 cases of adenocarcinoma, EMpe showed cells with short microvilli in 9 (45%), and 11 were acellular (55%). EMpe identifies unequivocal morphological changes that are useful for the differential diagnosis of MPM or adenocarcinoma when the pleural effusion sample contains evaluable tumor cells.

In plain English

This study, from the Instituto Nacional de Cancerología in Mexico City, tested whether examining pleural effusion fluid (fluid that collects around the lung) under an electron microscope could help tell malignant pleural mesothelioma apart from lung adenocarcinoma. The authors studied fluid samples from 25 patients (10 men, 15 women). Biopsy and tissue staining confirmed 5 cases of mesothelioma and 20 of lung adenocarcinoma. Asbestos exposure history was taken from clinical records: 3 of the 5 mesothelioma patients (60%) and 2 of the 20 adenocarcinoma patients (10%) had one. Electron microscopy showed features typical of mesothelioma, mainly long microvilli, in 2 of the 5 mesothelioma samples (40%); the other 3 (60%) contained no cells. It showed features typical of adenocarcinoma, mainly short microvilli, in 9 of the 20 adenocarcinoma samples (45%); 11 (55%) contained no cells. The authors concluded that the method is useful for telling the two cancers apart when the fluid contains tumor cells that can be evaluated. They named the small number of samples and inadequate samples as limitations.

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: Diagnostic study of a small series of selected patients (described by the authors as a cohort), comparing electron microscopy of pleural effusion fluid with biopsy-based diagnosis
• Who was studied: 25 patients (10 males, 15 females; mean age 65 years, range 35 to 84) admitted to the Instituto Nacional de Cancerología, Mexico City, with pleural effusion. Biopsy confirmed 5 malignant pleural mesotheliomas and 20 lung adenocarcinomas. Study dates are not given.
• Exposure: The study examined a diagnostic method: electron microscopy of centrifuged pleural effusion fluid, compared against biopsy with immunohistochemistry. Asbestos exposure history was only recorded from clinical records. No fiber types, jobs or doses are reported.
• Main results:
  • In the 5 mesothelioma samples, electron microscopy identified mesothelioma features (long microvilli) in 2 (40%).
  • 3 of the 5 mesothelioma samples (60%) and 11 of the 20 adenocarcinoma samples (55%) contained no cells and could not be evaluated.
  • In the 20 adenocarcinoma samples, electron microscopy showed the typical adenocarcinoma pattern in 9 (45%): short microvilli, secretory vacuoles, junctional complexes and intracytoplasmic lumens.
  • A history of asbestos exposure was present in 3 of 5 mesothelioma patients (60%) and 2 of 20 adenocarcinoma patients (10%).
• The authors' conclusion: The authors concluded that electron microscopy of pleural effusion fluid identifies morphological changes that are useful for distinguishing malignant pleural mesothelioma from adenocarcinoma when the sample contains evaluable tumor cells. They said further study is needed.
• Limitations the authors state:
  • Small number of samples, which the authors partly attribute to the low incidence of mesothelioma
  • Inadequate samples, which can hinder diagnosis when technical expertise is low
  • Some institutions do not have an electron microscope
  • Not all mesotheliomas produce effusions, and sarcomatoid mesotheliomas are virtually never diagnosed from effusion cytology

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 Effusion, Cytology, Pleural Mesothelioma, Lung Adenocarcinoma, Immunohistochemistry, Differential Diagnosis, Mesothelioma, Adenocarcinoma.

Related studies

• The diagnostic utility of D2-40, calretinin, CK5/6, desmin and MOC-31 in the differentiation of mesothelioma from adenocarcinoma in pleural effusion cytology — T.S. Hyun, M. Barnes, et al. (2012)
• Diagnostic usefulness of EMA, IMP3, and GLUT-1 for the immunocytochemical distinction of malignant cells from reactive mesothelial cells in effusion cytology using cytospin preparations — K. Ikeda, G. Tate, et al. (2011)
• Claudin-4 immunohistochemistry is highly effective in distinguishing adenocarcinoma from malignant mesothelioma in effusion cytology — V.Y. Jo, E.S. Cibas, et al. (2014)
• Small orangiophilic squamous-like cells: an underrecognized and useful morphological feature for the diagnosis of malignant mesothelioma in pleural effusion cytology — L. Chen, S.G. Caldero, et al. (2014)
• Diagnostic yield of pleural fluid cytology in malignant effusions: an Australian tertiary centre experience — P. Loveland, M. Christie, et al. (2018)
• Cytological differential diagnosis among adenocarcinoma, epithelial mesothelioma, and reactive mesothelial cells in serous effusions by immunocytochemistry — X.Y. Su, G.D. Li, et al. (2011)

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