An ultrastructural comparison of mesotheliomas with adenocarcinomas of the lung and breast

Our plain-English summary of An ultrastructural comparison of mesotheliomas with adenocarcinomas of the lung and breast, by M.J. Warhol, J.M. Corson (Human Pathology, 1985).

The study

• Authors: M.J. Warhol, J.M. Corson
• Journal: Human Pathology
• Published: 1985;16(1):50-5
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The ultrastructural features of 15 mesotheliomas were compared with those of equal numbers of adenocarcinomas of the lung and of the breast in a double-blind study. Combined quantitative and qualitative features were evaluated to provide criteria for distinguishing among these three tumors, which may present as either primary or metastatic pleural tumors. mesotheliomas could be distinguished from adenocarcinomas of the lung by length of microvilli (mean ratios of length to diameter [LDR], 15.7 and 8.7, respectively; P less than 0.01) and content of tonofilaments. Length of microvilli was also useful in distinguishing mesotheliomas from breast adenocarcinomas (mean LDR, 15.7 and 6.9, respectively; P less than 0.001). Adenocarcinomas of the lung could be distinguished from adenocarcinomas of the breast by tonofilament content and the presence of intracytoplasmic lumina. Combined quantitative and qualitative criteria are essential for maximal ultrastructural discrimination among these tumors.

In plain English

Pathologists used electron microscopy to compare 15 diffuse malignant mesotheliomas of the pleura (epithelial type) with 15 lung and 15 breast adenocarcinomas, in a double-blind study. The cases came from the files of Brigham and Women's Hospital. The article did not study asbestos exposure. It looked for features that help tell these tumors apart. The mean length-to-diameter ratio of surface microvilli was 15.7 in the mesotheliomas, 8.7 in the lung adenocarcinomas (P less than 0.01) and 6.9 in the breast adenocarcinomas (P less than 0.001). A ratio of 12 or greater occurred in ten of the 15 mesotheliomas but in only two of the 30 adenocarcinomas. Tonofilament scores of 2+ or greater were seen in 14 of 15 mesotheliomas but only one of 15 lung adenocarcinomas. Intracytoplasmic lumina appeared in seven mesotheliomas, eight breast adenocarcinomas and no lung adenocarcinomas. The authors suggested that some overlap with breast tumors may reflect suboptimal fixation of older tissue. They concluded that combining quantitative and qualitative criteria is essential for maximal discrimination among these tumors.

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: Comparative electron microscopy (ultrastructural) study of tumor tissue, evaluated double-blind
• Who was studied: Tumor samples from 45 patients, drawn from the electron microscopy laboratory files of the Department of Pathology, Brigham and Women's Hospital, Boston: 15 diffuse malignant mesotheliomas of the pleura (epithelial type), 15 peripheral lung adenocarcinomas (including four of the bronchoalveolar type) and 15 infiltrating ductal breast adenocarcinomas. Ten mesotheliomas and five lung adenocarcinomas had been in the authors' earlier study. No time period is given.
• Exposure: Not studied. The article compares tumor types under the microscope and does not address asbestos or any other exposure.
• Main results:
  • Mean length-to-diameter ratio (LDR) of microvilli was 15.7 in mesotheliomas versus 8.7 in lung adenocarcinomas (P less than 0.01).
  • Mean LDR was 15.7 in mesotheliomas versus 6.9 in breast adenocarcinomas (P less than 0.001).
  • An LDR of 12 or greater was seen in only two of the 30 adenocarcinomas (both lung) but in ten of the 15 mesotheliomas.
  • LDR was greater than 15 in eight of the 15 mesotheliomas (53 per cent).
  • Tonofilament scores of 2+ or greater were seen in 14 of 15 mesotheliomas and ten of 15 breast adenocarcinomas. Only one of 15 lung adenocarcinomas had a score of 2+ or greater. Mean scores were 2.6, 1.8 and 0.8 respectively.
  • Intracytoplasmic lumina were seen in seven of 15 mesotheliomas, eight of 15 breast adenocarcinomas and none of the lung adenocarcinomas.
  • LDR alone distinguished mesotheliomas from breast adenocarcinomas in 26 of 30 cases. Mesotheliomas with LDRs of less than 10 were indistinguishable from breast adenocarcinomas.
  • Lamellar bodies were found only in lung adenocarcinomas, in three of 15 cases. The authors judged them not a highly useful discriminant.
• The authors' conclusion: The authors concluded that combining quantitative and qualitative ultrastructural criteria is essential for maximal discrimination among mesotheliomas and adenocarcinomas of the lung and breast.
• Limitations the authors state:
  • The overlap in LDR between mesotheliomas and breast adenocarcinomas may have resulted from suboptimal fixation. Most lower LDR values in mesotheliomas came from tissue fixed years earlier in a less than optimal way.

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: Mesothelioma, Adenocarcinoma.

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• Differential Diagnosis of Epithelioid Malignant Mesothelioma With Lung and Breast Pleural Metastasis: A Systematic Review Compared With a Standardized Panel of Antibodies-A New Proposal That May Influence Pathologic Practice — N. Le Stang, L. Burke, et al. (2020)

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