An unusual isolated anterior mediastinal lesion

Our plain-English summary of An unusual isolated anterior mediastinal lesion, by N. Quigley, L. Lang-Lazdunski, C. Boily-Daoust, et al (Respirology Case Reports, 2022).

The study

• Authors: N. Quigley, L. Lang-Lazdunski, C. Boily-Daoust, C. Couture, M. Fortin
• Journal: Respirology Case Reports
• Published: 2022;10(11):e01059
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant pleural mesothelioma (MPM) is an infrequent tumour of poor prognosis with a strong association with asbestos exposure. Pleural effusion or thickening is the most common radiological finding. Thoracoscopic biopsy is the diagnostic modality of choice. In our report, we present the case of a career welder who consulted with vocal cord palsy and an atypical anterior mediastinal lesion. An EBUS-TBNA-guided biopsy and a thorough cytological assessment led to an unexpected diagnosis of epithelioid MPM. A localized anterior mediastinal lesion is an extremely infrequent presentation of MPM that deserves clinical recognition.

© 2022 The Authors. Respirology Case Reports published by John Wiley & Sons Australia, Ltd on behalf of The Asian Pacific Society of Respirology.

In plain English

This case report from Quebec, Canada, described one patient: a 61-year-old career welder with progressive hoarseness and a paralyzed right vocal cord. CT scans showed a 28 by 25 by 15 mm lesion in the upper front of the chest between the lungs (the antero-superior mediastinum). Doctors first thought it was an enlarged lymph node, possibly pressing on the nerve to the voice box. No fluid around the lungs and no pleural lesion was found. Cells were sampled with a needle passed through an airway scope (EBUS-TBNA) and tested with a panel of markers. This led to a diagnosis of epithelioid malignant pleural mesothelioma. The authors wrote that the patient's work-related asbestos exposure further supported the diagnosis, but gave no details of that exposure. Three months later the mass had grown to 6.1 cm and was judged inoperable. The patient was referred for chemotherapy. The authors noted that only two similar cases had been described before, none with vocal cord paralysis. They suggested including mesothelioma among possible diagnoses for an atypical mediastinal lesion with a pleural base.

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 61-year-old man, a career welder, with a 25 pack-year smoking history (quit more than 20 years earlier), seen at the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Canada; dates of care not stated
• Exposure: Occupational asbestos exposure is mentioned without detail (no fiber type, products, duration or dose given); the patient worked as a career welder
• Main results:
  • The patient had right vocal cord paralysis, confirmed by rhinolaryngoscopy
  • CT showed a 28 by 25 by 15 mm lesion of the antero-superior mediastinum with no other abnormalities, including no pleural effusion or pleural lesion
  • PET showed the mediastinal lesion to be strongly hypermetabolic, with no other hypermetabolic sites
  • Needle aspirate cytology showed clusters of malignant epithelioid cells. On immunohistochemistry the cells were positive for calretinin, Wilms' tumour-1, podoplanin/D2-40, cytokeratins 5/6 and AE1/3. They were negative for TTF-1, napsin A, p40, cytokeratin 20, BerEP4 and claudin 4. Malignant epithelioid mesothelioma was diagnosed.
  • On repeat CT 3 months later, the mass had grown to 6.1 cm in diameter and surrounded major blood vessels
  • The lesion was deemed inoperable because of its closeness to major blood vessels
  • The patient was referred to medical oncology for chemotherapy with cisplatin, pemetrexed and bevacizumab; no later outcome was reported
• The authors' conclusion: The authors stated that malignant pleural mesothelioma appearing as a localized antero-superior mediastinal lesion is extremely infrequent, with only two prior cases described and none with vocal cord paralysis. They suggested including mesothelioma in the extended differential diagnosis of an atypical mediastinal lesion with a pleural base.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Prognosis, Asbestos Exposure, Pleural Effusion, Thoracoscopic Biopsy, Biopsy, Epithelioid.

Related studies

• Minimally invasive, ionizing-free, and ultrasound-guided technique to biopsy anterior mediastinal masses: first 60 cases — B. Lorenzati, R. Cristofori, et al. (2018)
• A comparative evaluation of intrathoracic latissimus dorsi and serratus anterior muscle transposition — M.K. Widmer, T. Krueger, et al. (2000)
• Anterior cingulotomy improves malignant mesothelioma pain and dyspnoea — E.A. Pereira, M. Paranathala, et al. (2014)
• The detection of thoracic abnormalities using posterior-anterior (PA) vs PA and oblique roentgenograms — R.B. Reger, R.G. Ames, et al. (1982)
• The serratus anterior muscle on chest radiographs — D. Gilmartin (1979)
• Asbestosis and the serratus anterior muscle — J.D. Collins, R.K. Brown, et al. (1983)

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