The World Health Organization histological typing of lung tumours. Second edition

Our plain-English summary of The World Health Organization histological typing of lung tumours. Second edition, by World Health Organization (1982).

The study

• Author: World Health Organization
• Published: Am. J. Clin. Pathol. 77: 123-136 (received June 18, 1981; accepted for publication July 13, 1981) (1982)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This article is not a research study. It is the second edition of the World Health Organization's histological classification of lung tumours: agreed categories, definitions and explanatory notes that pathologists use to name tumours seen under the microscope. It revised the first edition, published in 1967. A WHO consultation in 1977 reviewed criticisms of the 1967 version, and a WHO meeting of pathologists in Geneva in October 1977 drew up the revision. The document kept the earlier definition of squamous cell carcinoma, divided small cell carcinoma into subtypes, and grouped several forms under adenocarcinoma. It stated that tumour type should be decided by light microscopy. It divided mesothelial tumours into epithelial, fibrous (spindle-cell) and biphasic types, with benign and malignant forms. It stated that diffuse mesotheliomas of the pleura are malignant, that most are biphasic, and that malignant localized mesotheliomas are very rare. It also stated that diffuse mesothelioma is associated with exposure to asbestos, particularly the blue form (crocidolite). The document presented no data of its own on this point.

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: Expert classification document (revised WHO histological classification of lung tumours, second edition); not a study of patients or data
• Who was studied: No patients or subjects were studied. The classification was prepared at a WHO meeting of pathologists held in Geneva, 24 to 28 October 1977, following a 1977 WHO consultation on the 1967 classification.
• Exposure: No exposure was studied. The only mention of asbestos is a statement in the mesothelial tumours section that diffuse mesothelioma is associated with asbestos exposure, particularly crocidolite (blue asbestos).
• Main results:
  • Mesothelial tumours (tumours of the lining of the pleura) are classified into fibrous, epithelial and biphasic subtypes.
  • Diffuse mesotheliomas of the pleura are described as malignant and as involving the parietal and visceral surfaces.
  • Most diffuse mesotheliomas are described as biphasic, although monomorphic forms occur.
  • Malignant localized mesotheliomas are described as very rare and of fibrous type.
  • Squamous cell carcinoma (epidermoid carcinoma) keeps the definition used in the 1967 edition.
  • Small cell carcinoma is divided into subtypes, starting with oat-cell carcinoma.
  • Adenocarcinoma includes acinar, papillary and bronchiolo-alveolar forms.
  • Tumour type is to be decided from light microscopic observations.
• The authors' conclusion: The WHO meeting formulated the revised classification, definitions and explanatory notes and recommended them for publication.

Topics

Medical terms in this study, explained in our Lexicon: Histological Subtype, Squamous Cell Carcinoma, Carcinoma, Adenocarcinoma, Biphasic Mesothelioma, Mesothelioma, Pleura, Localized Malignant Mesothelioma.

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