Malignant Mesothelioma Mimicking Invasive Mammary Carcinoma in a Male Breast

Our plain-English summary of Malignant Mesothelioma Mimicking Invasive Mammary Carcinoma in a Male Breast, by M.M. Desouki, D.J. Long (Case Reports in Oncological Medicine, 2015).

The study

• Authors: M.M. Desouki, D.J. Long
• Journal: Case Reports in Oncological Medicine
• Published: 2015;2015:298523
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant mesothelioma is an uncommon tumor with strong association with asbestos exposure. Few cases of malignant pleural mesothelioma metastatic to the female breast have been reported. Herein, we presented, for the first time, a case of locally infiltrating malignant pleural mesothelioma forming a mass in the breast of a male as the first pathologically confirmed manifestation of the disease. Breast ultrasound revealed an irregular mass in the right breast which involves the pectoralis muscle. Breast core biopsy revealed a proliferation of neoplastic epithelioid cells mimicking an infiltrating pleomorphic lobular carcinoma. IHC studies showed the cells to be positive for calretinin, CK5/6, WT1, and CK7. The cells were negative for MOC-31, BerEp4, ER, and PR. A final diagnosis of malignant mesothelioma, epithelioid type, was rendered. This case demonstrates the importance of considering a broad differential diagnosis in the setting of atypical presentation with application of a panel of IHC markers.

In plain English

This case report described one patient, a 77-year-old man who had a firm lump in his right breast. Eleven months earlier he had right chest surgery for a complicated fluid collection, and the tissue removed then was read as pleural plaque with no evidence of cancer. He reported an occupational history of asbestos exposure; the article does not name a fiber type. Ultrasound showed a mass measuring 5.6 by 2.9 by 3.6 cm that involved the chest muscle. A CT scan suggested direct spread from the pleura through the chest wall rather than a metastasis. The biopsy looked like a type of breast cancer (pleomorphic lobular carcinoma), but stains for marker proteins led to a diagnosis of malignant mesothelioma, epithelioid type. The authors raised the possibility that the earlier surgery contributed to the spread into the chest wall and breast. To their knowledge, it was the first such case reported in a male breast. The authors concluded that unusual presentations call for considering a broad range of diagnoses and using a panel of markers.

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 (single patient)
• Who was studied: One 77-year-old man with a mass in the right breast. Two of his siblings had breast cancer and a BRCA1 mutation; his own BRCA status was unknown. The article gives no location or date for the case.
• Exposure: Occupational asbestos exposure reported by the patient. No fiber type, job, product or dose is given.
• Main results:
  • Eleven months before the breast mass, tissue from his right chest surgery (pleural decortication) was reviewed by lung pathologists. It was reported as pleural plaque with dense scarring and calcification and no evidence of malignancy.
  • The chest CT showed extensive right-sided pleural thickening and a calcified pleural plaque on the left side.
  • Breast ultrasound showed an irregular mass in the right breast measuring 5.6 by 2.9 by 3.6 cm.
  • The CT scan showed a pleural-based process extending through the chest wall muscle into the fat under the skin. This indicated direct spread rather than a metastasis to the breast.
  • The breast needle core biopsy showed tumor cells that resembled an infiltrating pleomorphic lobular carcinoma (a type of breast cancer).
  • The tumor cells stained positive for WT1, calretinin, CK5/6 and CK7.
  • The tumor cells stained negative for MOC-31, BerEp4, ER, PR, S100 protein and HMB-45.
  • Based on the appearance of the cells and the staining results, the final diagnosis was malignant mesothelioma, epithelioid type.
  • The authors suggested that the earlier chest surgery, together with mesothelioma's tendency to spread through surgical sites, might possibly have caused the chest wall and breast involvement.
  • To the authors' knowledge, no metastatic or locally extended malignant mesothelioma in a male breast had been reported in the English-language literature.
• The authors' conclusion: The authors concluded that when spread from outside the breast is suspected, a panel of immunohistochemistry markers may help. They also concluded that malignant mesothelioma should be considered among the possible tumors.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Carcinoma, Asbestos Exposure, Pleural Mesothelioma, Ultrasound, Biopsy, Epithelioid, Pleomorphic.

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• Metastases to the breast: differential diagnosis from primary breast carcinoma — B. Vergier, M. Trojani, et al. (1991)
• GATA-3 and FOXA1 expression is useful to differentiate breast carcinoma from other carcinomas — D.G. Davis, M.T. Siddiqui, et al. (2016)
• Diagnostic utility of immunohistochemistry in distinguishing between epithelioid pleural mesotheliomas and breast carcinomas: a comparative study — N.G. Ordóñez, A.A. Sahin (2014)
• Expression of calretinin by breast carcinoma and the potential for misdiagnosis of mesothelioma — G. Powell, H. Roche, et al. (2011)

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