Concomitant diagnosis of hypersensitivity pneumonitis and localized epithelioid mesothelioma: a rare case report

Our plain-English summary of Concomitant diagnosis of hypersensitivity pneumonitis and localized epithelioid mesothelioma: a rare case report, by S.L. Martini, T.K.B.D. Silva, B.C. Furian, et al (Einstein, 2025).

The study

• Authors: S.L. Martini, T.K.B.D. Silva, B.C. Furian, A.C.S. Klein, J.G.S. Klein, C.S. Möller, D.M.P. Garcia, G.B. Ferreira
• Journal: Einstein
• Published: 2025;23:eRC1296
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Hypersensitivity pneumonitis is an inflammatory lung disease caused by antigen inhalation after sensitization. Here, we report a rare case of the simultaneous diagnosis of hypersensitivity pneumonitis and epithelioid mesothelioma, a subtype of malignant mesothelioma. A 71-year-old man presented with an occasional dry cough and exertional dyspnea that had persisted for about 1 year. He reported walking daily in a park with a considerable number of birds during same period. Functional evaluation revealed a mild restrictive ventilatory disorder. High-resolution computed tomography showed nonspecific peripheral interstitial lung involvement along with signs of bronchopathy and diffuse bronchiolopath without honeycombing or bronchiectasis. Owing to the patient's clinical history and the presence of a restrictive ventilatory disorder, a biopsy was performed for diagnostic clarification. Pathological examination revealed hypersensitive pneumonitis associated with epithelioid mesothelioma. Surgical resection of the mesothelioma and avoidance of occupational exposure resulted in complete regression of symptoms and improvement in radiological findings. A report on this rare concomitant diagnosis of the hypersensitivity pneumonitis and epithelioid mesothelioma is essential for advancements in medicine.

In plain English

This article was a case report about one 71-year-old man from Taquara, Rio Grande do Sul, Brazil, who had an occasional dry cough and shortness of breath on exertion for about a year. He had been taking daily walks of about 50 minutes in a park with a moderate number of birds, so doctors suspected hypersensitivity pneumonitis, an allergic inflammation of the lungs. Breathing tests showed a mild restrictive pattern. CT scans showed lung inflammation that increased between 2019 and 2020. A surgical lung biopsy in November 2020 showed changes typical of hypersensitivity pneumonitis. It also showed, unexpectedly, a 7.32 mm epithelioid mesothelioma under the pleura of the right lower lobe, which was removed. A second specialized center confirmed the diagnosis. After he stopped the park walks, his condition improved without oral corticosteroids. A January 2021 CT showed almost complete clearing of the lung infiltrates. The authors wrote that he had no asbestos exposure and suggested a possible role for genetic changes such as BAP-1 mutations. The authors concluded that the coexistence of these two diseases is an unexplored field.

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 71-year-old Caucasian man from Taquara, RS, Brazil, a non-smoker, seen by a pulmonologist from January 2018, with follow-up to January 2021
• Exposure: The suspected cause of the hypersensitivity pneumonitis was bird exposure during daily walks in a park. The authors state there was no asbestos exposure.
• Main results:
  • In 2018, spirometry showed a mild restrictive ventilatory disorder.
  • The December 2019 CT also showed a small thickening of the diaphragmatic pleura on the right side.
  • A follow-up CT in May 2020 showed increased lung infiltration compared with the first scan.
  • The biopsy found a 7.32 mm subpleural epithelioid mesothelioma in the right lower lobe, which was surgically removed, together with fibrosis and inflammation characteristic of hypersensitivity pneumonitis.
  • Immunohistochemical staining of the samples was positive for CK7, CK5/6, WT1, calretinin, BAP-1 and D2-40.
  • A second specialized diagnostic center reviewed and confirmed the diagnosis.
  • After the patient stopped the park walks, a January 2021 CT showed almost complete resolution of the lung infiltrates.
  • The patient did not need oral corticosteroids because his shortness of breath was mild.
  • The authors describe the mesothelioma as found incidentally at an early stage.
• The authors' conclusion: The authors concluded that the case shows the importance of a thorough clinical history. They also concluded that the coexistence of hypersensitivity pneumonitis and mesothelioma is an unexplored field needing better understanding. They suggested that the absence of asbestos exposure points to a possible role for genetic alterations such as BAP-1 mutations.

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: Pneumonitis, Epithelioid, Mesothelioma, Dyspnea, Interstitial, Honeycombing, Biopsy, Surgical Resection.

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