Hibernoma-like Changes and TFE3 Expression in Mesothelioma Mimicking TFE3-Translocation Renal Cell Carcinoma: A Diagnostic Pitfall

Our plain-English summary of Hibernoma-like Changes and TFE3 Expression in Mesothelioma Mimicking TFE3-Translocation Renal Cell Carcinoma: A Diagnostic Pitfall, by D. Hoton, M. Luyckx, C. Galant, et al (International Journal of Surgical Pathology, 2021).

The study

• Authors: D. Hoton, M. Luyckx, C. Galant, H. Dano
• Journal: International Journal of Surgical Pathology
• Published: 2021;29(6):627-630
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The long delay between asbestos exposure and the development of mesothelioma will likely result in an increased incidence of mesothelioma in our industrialized societies. Radiation therapy is another factor known to induce these tumors. We describe a rare case of foamy looking mesothelioma in a 63-year-old patient with a long oncology history of a supposed peritoneal carcinomatosis. The pathologist was faced with a diagnostic pitfall as this peritoneal clear cell tumor expressed transcription factor binding to immunoglobulin heavy constant mu enhancer 3 (TFE3) at the nuclear level. Fortunately, the pathologist performed an extensive panel of immunomarkers, leading to a final diagnosis of epithelioid mesothelioma. Thus, we describe the first case of mesothelioma expressing TFE3. Note that there was no rearrangement of TFE3 in fluorescence in situ hybridization.

In plain English

This article is a case report about one 63-year-old woman. She had a long history of other tumors and came in with abdominal pain. Imaging suggested cancer spread across the peritoneum, the lining of the abdomen. Under the microscope, many tumor cells had pale, foamy-looking cytoplasm resembling a hibernoma, a fatty tumor. Because this appearance has been described in kidney cancer, the pathologists tested for TFE3, a protein linked to one kind of kidney cancer. The tumor showed diffuse TFE3 staining in the cell nuclei, but its overall staining pattern did not match a kidney origin. Further stains pointed to mesothelioma: calretinin was intensely positive, WT1 was weakly positive, and BAP1 was lost. A genetic test (FISH) found no TFE3 rearrangement. The final diagnosis was epithelioid mesothelioma of the peritoneum. The article does not report whether she had been exposed to asbestos or radiation. It reports that she was a smoker. The authors concluded that, to their knowledge, this was the first reported peritoneal mesothelioma with diffuse nuclear TFE3 staining and this foamy appearance.

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
• Who was studied: One 63-year-old woman with an extensive history of other tumors (meningiomas, thyroid, colon, cervical and pancreatic tumors, among others); the authors are based in Brussels, Belgium; dates of care not stated
• Exposure: No asbestos or radiation exposure is reported for this patient; the article reports that she was an active smoker with a 50 pack-year history
• Main results:
  • Many tumor cells in the peritoneal cytology and biopsies had clear, microvacuolated cytoplasm with a foamy appearance resembling hibernoma cells
  • The tumor showed diffuse nuclear staining for TFE3, of moderate-to-strong intensity
  • The tumor was positive for CK7 and negative for CK20, PAX8, SATB2, ER and PR; the authors judged that the staining profile did not match a kidney origin
  • Mesothelial markers: calretinin showed intense cytoplasmic and nuclear staining and WT1 showed weak nuclear staining
  • BAP1 expression was lost in the cell nuclei
  • FISH showed no TFE3 translocation in the tumor
  • FISH for p16 did not show homozygous deletion of CDKN2A
  • The final diagnosis was epithelioid mesothelioma (malignant peritoneal epithelioid mesothelioma)
• The authors' conclusion: The authors concluded that, to their knowledge, this was the first reported case of peritoneal mesothelioma with diffuse nuclear TFE3 positivity and hibernoma-like foamy morphology, mimicking a renal cell carcinoma with hibernoma-like changes
• Limitations the authors state:
  • The result of the patient's germline (inherited) mutation testing was not known when the article was written

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Translocation, Carcinoma, Asbestos Exposure, Epithelioid, Fluorescence In Situ Hybridization (FISH).

Related studies

• Metastatic renal cell carcinoma mimicking pleural mesothelioma — D.R. Taylor, W. Page, et al. (1987)
• Small cell mesothelioma: A rare entity and diagnostic pitfall mimicking small cell lung carcinoma on fine-needle aspiration — Y. Zhang, A. Afify, et al. (2016)
• ALK positive malignant peritoneal mesothelioma mimicking inflammatory myofibroblastic tumour: a diagnostic pitfall — A. Louw, C. Wallace, et al. (2020)
• A comparative immunohistochemical study of malignant mesothelioma and renal cell carcinoma: the diagnostic utility of Leu-M1, Ber EP4, Tamm-Horsfall protein and thrombomodulin — R.L. Attanoos, H. Goddard, et al. (1995)
• Value of PAX8, PAX2, napsin A, carbonic anhydrase IX, and claudin-4 immunostaining in distinguishing pleural epithelioid mesothelioma from metastatic renal cell carcinoma — N.G. Ordóñez (2013)
• The value of 'mesothelium-associated' antibodies in distinguishing between metastatic renal cell carcinomas and mesotheliomas — M. Osborn, N. Pelling, et al. (2002)

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