Malignant pleural neoplasm with both differentiation of epithelioid mesothelioma and squamous-cell carcinoma, a rare phenomena

Our plain-English summary of Malignant pleural neoplasm with both differentiation of epithelioid mesothelioma and squamous-cell carcinoma, a rare phenomena, by A. Re, D. Shersher, A. Allen, et al (Diagnostic Cytopathology, 2021).

The study

• Authors: A. Re, D. Shersher, A. Allen, R. Schwarting, S. Ren
• Journal: Diagnostic Cytopathology
• Published: 2021;49(6):E234-E237
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma, a neoplasm arising within the serosal surfaces, has been linked closely to asbestos exposure. We present a case of 72-year-old male with a 27 year work-related history of asbestos exposure who presented with dyspnea. Chest computed tomography scan showed a large, right pleural effusion with compressive right lung atelectasis. Biopsies, subsequent pleurectomy and lung wedge resections revealed epithelioid malignant mesothelioma with associated focal non-keratinizing squamous-cell carcinoma, supported by extensive immunohistochemical stains and molecular studies. The patient was treated with 6 cycles of carboplatin/pemetrexed, showing no new metastases. Seven months post-treatment, the patient presented with progressive dyspnea and large pleural effusions. Bilateral pleural fluid was collected and showed malignant epithelioid cells, morphologically similar to the patient's pleural neoplastic cells. However, the tumor was positive for squamous cells markers and showed BAP1 loss, while negative for mesothelial markers. The findings support the diagnosis of squamous-cell carcinoma and were consistent with the patient's previously diagnosed pleural neoplastic origin. A malignant mesothelioma associated with squamous-cell carcinoma is a rare phenonmenon. To our knowledge, only two case reports are available in current literature. This unique case shows a single pleura tumor differentiating as both malignant mesothelioma and squamous-cell carcinoma. Squamous-cell carcinoma is the predominating malignancy seen within the bilateral pleural effusions, a potential pitfall for cytology specimen diagnosis.

© 2020 Wiley Periodicals LLC.

In plain English

This brief report described one patient: a 72-year-old man with 27 years of work-related asbestos exposure. The article did not name the fiber type or the job. He came to the emergency department short of breath, and a chest CT scan showed a large fluid build-up around the right lung (pleural effusion). Biopsy and surgical tissue showed epithelioid malignant mesothelioma of the pleura, with a small area of non-keratinizing squamous-cell carcinoma. Genetic testing found loss of BAP1 and CDKN2A/B, among other changes. He then had 6 cycles of carboplatin/pemetrexed chemotherapy. Two months after chemotherapy, according to the case description (the abstract instead says seven months after treatment), he returned with fluid around both lungs. The cancer cells in that fluid tested as squamous-cell carcinoma rather than mesothelioma, and had also lost BAP1. No other tumor was found, and spread from his earlier prostate cancer was ruled out. The authors concluded that the squamous-cell carcinoma came from the same pleural tumor. They warned that such cases could be misdiagnosed as squamous-cell carcinoma spread from elsewhere.

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 72-year-old male patient with a history of prostatic adenocarcinoma, reported by authors at Cooper University Hospital, Camden, New Jersey; dates of care not given
• Exposure: Work-related asbestos exposure lasting 27 years; fiber type, products and job not specified
• Main results:
  • Chest CT showed a large right pleural effusion with compressive right lung atelectasis
  • Biopsies and surgical specimens were diagnosed as epithelioid mesothelioma with associated focal non-keratinizing squamous-cell carcinoma
  • Molecular testing of the pleural resection specimen showed BAP1 loss of exons 1 to 3, CDKN2A/B loss, DNMT3A rearrangement and MTAP loss, among other findings
  • After 6 cycles of carboplatin/pemetrexed, no new metastases were seen
  • The case description says the patient returned with progressive dyspnea and large pleural effusions seven months later, which it specifies as 2 months after chemotherapy; the article's abstract instead says seven months post-treatment
  • Tumor cells in the bilateral pleural fluid were positive for squamous-cell markers, negative for mesothelial markers, and had lost BAP-1 expression
  • No other neoplasm or squamous-cell carcinoma was found elsewhere in the body, and metastatic prostatic and urothelial carcinoma were excluded
  • The authors judged the squamous-cell carcinoma to be of pleural neoplastic origin
• The authors' conclusion: The authors concluded that pleural tumors with extensive squamous differentiation could be misdiagnosed as metastatic squamous-cell carcinoma, and that mesothelioma should be included in the differential diagnosis

Topics

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

Medical terms in this study, explained in our Lexicon: Neoplasm, Epithelioid, Mesothelioma, Carcinoma, Malignant Mesothelioma, Serosal Surface, Asbestos Exposure, Dyspnea.

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