L1CAM expression in cystic mesothelial lesions: a comparison with adenomatoid tumours, well-differentiated papillary mesothelial tumours and malignant mesotheliomas

Our plain-English summary of L1CAM expression in cystic mesothelial lesions: a comparison with adenomatoid tumours, well-differentiated papillary mesothelial tumours and malignant mesotheliomas, by G. Karpathiou, F. Casteillo, M. Dridi, et al (Histopathology, 2021).

The study

• Authors: G. Karpathiou, F. Casteillo, M. Dridi, A. Papoudou-Bai, J.M. Dumollard, M. Peoc'h
• Journal: Histopathology
• Published: 2021;79(2):272-274
• Type of article: Letter
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This letter reported a study of whether L1 cell adhesion molecule (L1CAM) is expressed in cystic mesothelial lesions. Earlier studies had found TRAF7 mutations and L1CAM expression in adenomatoid tumours (ATs) and well-differentiated papillary mesothelial tumours (WDPMTs). The authors, from pathology departments in Saint-Etienne, France, and Ioannina, Greece, retrospectively studied 57 consecutive cystic mesothelial lesions. These were solitary (38) or multiple (19), and peritoneal (47) or pericardial (10). For comparison they included 18 ATs, 7 WDPMTs and 24 pleural epithelioid malignant mesotheliomas (MMs). Immunohistochemistry for L1CAM (clone UJ127.11) was performed on whole tissue sections, and staining was recorded by intensity and extent. None of the cystic mesothelial lesions expressed L1CAM. L1CAM expression was found in 13 of 18 ATs (72.2%), focal in 6, and in 3 of 7 WDPMTs (42.8%), with mild and focal staining. None of the MMs expressed L1CAM. The authors concluded that the absence of L1CAM probably suggests a different etiopathogenetic model for cystic mesothelial lesions than for ATs and WDPMTs. They also concluded that L1CAM may not be universally expressed by ATs and WDPMTs and should be interpreted with caution if used for diagnosis. With this clone, positivity would favour AT/WDPMT over MM or cystic lesions. However, they noted that this clone shows the lowest positivity of L1CAM antibodies and that other clones are expressed by MMs.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This was a short research letter by pathologists at university hospitals in Saint-Etienne, France, and Ioannina, Greece. They looked back at tissue from 57 consecutive cystic mesothelial lesions, which are fluid-filled lesions of the lining of body cavities. Of these, 47 were in the peritoneum (abdominal lining) and 10 in the pericardium (lining around the heart). They stained the tissue for a protein called L1CAM. For comparison, they also stained 18 adenomatoid tumours and 7 well-differentiated papillary mesothelial tumours, both benign, and 24 malignant mesotheliomas, all pleural and epithelioid. None of the 57 cystic lesions and none of the 24 malignant mesotheliomas showed L1CAM. The protein was found in 13 of the 18 adenomatoid tumours (focal in 6) and in 3 of the 7 papillary tumours (mild and focal). The authors concluded that L1CAM is not found in cystic mesothelial lesions, which probably suggests these lesions arise differently from the two benign tumours. They also said L1CAM staining should be interpreted with caution when used for diagnosis, partly because the antibody they used detects L1CAM least often of the available antibodies. The article does not discuss asbestos exposure.

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: Retrospective laboratory (immunohistochemistry) study of a case series, published as a correspondence letter
• Who was studied: 57 consecutive cystic mesothelial lesions (38 solitary, 19 multiple). Comparison groups were 18 adenomatoid tumours, 7 well-differentiated papillary mesothelial tumours (5 in women, 2 in men) and 24 malignant mesotheliomas (20 in men, 4 in women, all pleural and epithelioid). Authors are from pathology departments in Saint-Etienne, France and Ioannina, Greece. Dates of diagnosis are not given.
• Exposure: No asbestos or other environmental exposure was studied. The study measured L1CAM protein in tissue sections by immunohistochemistry, using antibody clone UJ127.11.
• Main results:
  • The cystic mesothelial lesions were peritoneal in 47 cases (82.5%) and pericardial in 10 cases (17.5%).
  • None of the 57 cystic mesothelial lesions expressed L1CAM.
  • Adenomatoid tumours: L1CAM was found in 13 out of 18 (72.2%), and the staining was focal in 6 of them.
  • Well-differentiated papillary mesothelial tumours: L1CAM was found in 3 out of 7 (42.8% as printed), with mild and focal expression.
  • Malignant mesotheliomas: none of the 24 showed L1CAM expression.
• The authors' conclusion: The authors concluded that L1CAM is not found in cystic mesothelial lesions. They also concluded that, in their series of adenomatoid tumours, L1CAM was not as universally present as expected, so its staining should be interpreted with caution when used for diagnosis. They wrote that the absence of L1CAM probably suggests a different origin for cystic lesions compared with the two benign tumours.
• Limitations the authors state:
  • The antibody clone used (UJ127.11) has the lowest positivity of the L1CAM antibodies, and other clones are expressed by malignant mesotheliomas, so the authors say caution is needed.
  • Factors in the tumours themselves, or in how the samples were handled before testing, could affect the staining result.

Topics

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

Medical terms in this study, explained in our Lexicon: Adenomatoid Tumor, Well-Differentiated, Malignant Mesothelioma, Pathology, Pericardial, Epithelioid, Immunohistochemistry.

Related studies

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• Microcystic variant of localized malignant mesothelioma accompanying an adenomatoid tumor-like lesion — H. Umezu, K. Kuwata, et al. (2002)
• Immunohistochemical evidence of the mesothelial histogenesis of a uterine adenomatoid tumor — Y. Satoh, M. Hiraguchi, et al. (1998)
• Composite multicystic mesothelioma and adenomatoid tumour of the uterus: different morphological manifestations of the same process? — J.K. Chan, M.H. Fong (1996)
• Well-Differentiated Papillary Mesothelial Tumor: An Unusual Radiologic Presentation: A Case Report — M. Abdelghafar, K. Anand, et al. (2023)
• Aberrant Pax-8 expression in well-differentiated papillary mesothelioma and malignant mesothelioma of the peritoneum: a clinicopathologic study — D. Xing, N. Banet, et al. (2018)

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