Mesothelioma of the tunica vaginalis with BerEp4 and LeuM1 expression: identification of cytoplasmic tonofilaments by electron microscopy is a key diagnostic feature

Our plain-English summary of Mesothelioma of the tunica vaginalis with BerEp4 and LeuM1 expression: identification of cytoplasmic tonofilaments by electron microscopy is a key diagnostic feature, by D. Shelton, N. Dalal (Journal of Clinical Pathology, 2012).

The study

• Authors: D. Shelton, N. Dalal
• Journal: Journal of Clinical Pathology
• Published: 2012;65(10):958-9
• Type of article: Case report, Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This short report described a single patient with a malignant tumour of the tunica vaginalis, a paratesticular site (next to the testis), from a pathology department in Manchester, UK. It gave no details of the patient's age, symptoms, treatment, outcome or any asbestos exposure. Under the microscope the tumour had a tubulopapillary pattern with abundant psammoma bodies and no sarcomatoid areas. The tumour cells stained positive for BerEP4 and showed focal but strong LeuM1 staining. The authors described these markers as typically negative in mesothelioma and positive in carcinoma. The cells were also positive for CK5/6, WT-1 and CK7, with only focal calretinin positivity. Electron microscopy showed occasional desmosomes, long microvilli and cytoplasmic tonofilaments, which the authors said favoured mesothelioma. The main alternative diagnosis was papillary serous carcinoma. The authors believed this was the first reported paratesticular mesothelioma with co-expression of both BerEp4 and LeuM1 and with abundant psammoma bodies. They concluded that the two tumours can be hard to tell apart even with staining, and that electron microscopy is warranted for a definitive diagnosis in such challenging cases.

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 report (a single patient, published as a short letter)
• Who was studied: One patient with a malignant tumour of the tunica vaginalis, reported by the Department of Cellular Pathology, The Christie NHS Foundation Trust, Manchester, UK. The article does not give age, dates or other patient details.
• Exposure: Not reported. The article does not mention asbestos or any other exposure history.
• Main results:
  • The tumour had a tubulopapillary architecture with abundant psammoma bodies, and no sarcomatoid areas were seen.
  • The tumour cells were positive for BerEP4 and showed focal but strong LeuM1 staining.
  • The tumour cells were also positive for CK5/6, WT-1 and CK7, with only focal calretinin positivity.
  • Vimentin, EMA, D2-40 and thrombomodulin were not tested in this case.
  • Electron microscopy showed occasional intercellular junctions including desmosomes, long microvilli and cytoplasmic tonofilaments. The authors said these features favoured a diagnosis of mesothelioma.
  • Paratesticular papillary serous carcinoma was the main alternative (differential) diagnosis considered in this case.
  • The authors stated that, to their knowledge, this was the first reported paratesticular mesothelioma with co-expression of both BerEp4 and LeuM1 and with abundant psammoma bodies.
• The authors' conclusion: The authors concluded that paratesticular malignant mesothelioma and papillary serous carcinoma can be difficult to distinguish, even with immunohistochemistry, and that electron microscopy is warranted for a definitive diagnosis in these challenging cases. They also suggested, tentatively, that a common cell of origin might explain the two tumours' overlapping features.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Tunica Vaginalis.

Related studies

• Malignant mesothelioma of the tunica vaginalis testis: diagnostic studies and differential diagnosis — S.S. Chekol, C.C. Sun (2012)
• Clinical Features and Outcomes of Tunica Vaginalis Mesothelioma: A Case Series From the National Institutes of Health — J.Y. An, D. Kim, et al. (2017)
• Malignant mesothelioma of the tunica vaginalis testis: report of first case with preoperative diagnosis — L. Japko, A.A. Horta, et al. (1982)
• A case of malignant mesothelioma pleural effusion with MOC-31, BerEP4, and calretinin expression — P. Zhao (2019)
• Malignant mesothelioma of tunica vaginalis testis — K.T. Chen, R.B. Arhelger, et al. (1982)
• Mesothelioma of the tunica vaginalis: a series of eight cases with uncertain malignant potential — F. Brimo, P.B. Illei, et al. (2010)

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