Biphasic malignant mesothelioma with epithelioid and sarcomatoid components (dedifferentiated mesothelioma) and intrapulmonary growth: a rare entity mimicking desquamative interstitial pneumonia

Our plain-English summary of Biphasic malignant mesothelioma with epithelioid and sarcomatoid components (dedifferentiated mesothelioma) and intrapulmonary growth: a rare entity mimicking desquamative interstitial pneumonia, by J. Laforga, A. Gonzalez Garcia (Journal of Clinical Pathology, 2020).

The study

• Authors: J. Laforga, A. Gonzalez Garcia
• Journal: Journal of Clinical Pathology
• Published: 2020;73(12):e8
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a single case report, published as a teaching case. It described a 54-year-old man who had symptoms of chronic obstructive pulmonary disease (COPD) and had smoked for many years. The article does not mention asbestos or any work exposure. A CT scan showed bullae in both lungs and a tumour measuring 35×25 mm in the right upper lobe, which looked like a tumour inside the lung. Surgeons removed that lobe, and the removed lesion measured 5×5 cm. Under the microscope the tumour had two parts. The epithelioid cells stained for calretinin, WT-1 and pan-keratin. A poorly differentiated spindle cell part did not stain for any of the markers tested. In places the epithelioid cells filled air spaces amid heavy inflammation, resembling a lung disease called desquamative interstitial pneumonia. The diagnosis was biphasic malignant mesothelioma with growth into the lung, which the authors called 'dedifferentiated mesothelioma'. The authors concluded that knowing these features can help prevent this tumour from being mistaken for an inflammatory lung disease, especially on core biopsies.

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 (teaching case, 'Virtual case of the month')
• Who was studied: One 54-year-old man with symptoms of chronic obstructive pulmonary disease (COPD), treated at Hospital de Denia, Spain
• Exposure: No asbestos or occupational exposure is mentioned. The only exposure reported is that the patient had smoked for many years.
• Main results:
  • A CT scan showed bilateral bullae and a tumour measuring 35×25 mm in the right upper lobe.
  • After right upper lobectomy, gross examination of the specimen showed a nodular lesion measuring 5×5 cm.
  • The epithelioid component showed strong, diffuse calretinin staining. It was also reported as multifocally positive for pan-keratin and WT-1.
  • The pleomorphic spindle cell (sarcomatoid) component did not stain with any of the antigens tested, including mesothelial markers. This led the authors to use the term 'dedifferentiated mesothelioma'.
  • In some areas the epithelioid cells grew into alveolar spaces with heavy inflammation, resembling desquamative interstitial pneumonia.
  • The final diagnosis was biphasic malignant mesothelioma with intrapulmonary growth.
• The authors' conclusion: The authors concluded that familiarity with these features can help prevent biphasic malignant mesothelioma from being misinterpreted as an inflammatory interstitial disease such as desquamative interstitial pneumonitis, especially on core biopsies.

Topics

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

Medical terms in this study, explained in our Lexicon: Biphasic Mesothelioma, Malignant Mesothelioma, Epithelioid, Sarcomatoid, Mesothelioma, Interstitial.

Related studies

• Diffuse intrapulmonary mesothelioma mimicking pulmonary lepidic adenocarcinoma: a rare case report and review of the literature — W. RanYue, W. ChunYan, et al. (2023)
• Desquamative interstitial pneumonia induced by metal exposure. A case report and literature review — T. Blin, A. De Muret, et al. (2020)
• Malignant pleural mesothelioma mimicking the intrapulmonary growth pattern of epithelioid hemangioendothelioma — Y. Muramatsu, K. Isobe, et al. (2014)
• Diffuse intrapulmonary malignant mesothelioma masquerading as interstitial lung disease: a distinctive variant of mesothelioma — B.T. Larsen, J.R. Klein, et al. (2013)
• Dyskeratosis congenita showing usual interstitial pneumonia — S. Imokawa, A. Sato, et al. (1994)
• Asbestosis and environmental causes of usual interstitial pneumonia — M. Gulati, C.A. Redlich (2015)

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