Case reports of primary pulmonary adenocarcinoma with pleural spread: so-called pseudomesotheliomatous adenocarcinoma

Our plain-English summary of Case reports of primary pulmonary adenocarcinoma with pleural spread: so-called pseudomesotheliomatous adenocarcinoma, by R. Saito, A. Kasajima, S. Taniuchi, et al (Pathology International, 2012).

The study

• Authors: R. Saito, A. Kasajima, S. Taniuchi, F. Fujishima, K. Ishida, Y. Nakamura, S. Yamanda, T. Takahashi, H. Hitomi, K. Murakami, M. Watanabe, H. Sasano
• Journal: Pathology International
• Published: 2012;62(10):709-15
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We report two autopsy cases of primary pulmonary adenocarcinoma associated with unusual pleural spread. Both patients had confirmed history of asbestos exposure. In the first patient the tumor was localized in one pulmonary lobe with marked infiltration into pleura, chest wall and diaphragm. In the second patient the entire right lung was covered by irregularly thickened tumor. Both tumors were mainly located in the extrapulmonary area and the intrapulmonary portions represented only minor components. Histologically, tumor cells demonstrated glandular and papillary growth patterns associated with focal hobnail-like features. Immunohistochemical evaluation revealed diffuse and marked immunoreactivity of TTF-1, CEA, CD15 and MOC31 in both cases, while calretinin, CK5/6, vimentin, thrombomodulin and HBME-1 were broadly positive in one case. D2-40 was not detected in either case. Examination using electron microscopy revealed the presence of sparse and short microvilli in tumor cells. All of the above findings are consistent with adenocarcinoma of the lung. Primary adenocarcinoma with a characteristic pleural extention grossly resembling malignant mesothelioma has been previously reported in the literature as pseudomesotheliomatous adenocarcinoma. This is the first report of pseudomesotheliomatous adenocarcinoma displaying variable immunoprofile with a diagnosis using electron microscopical examination. Additionally, we performed quantitative analysis of asbestos bodies in pseudomesotheliomatous adenocarcinoma.

© 2012 The Authors. Pathology International © 2012 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.

In plain English

This article reported two autopsy cases from Japan of primary lung adenocarcinoma that spread along the pleura in a way that resembled malignant pleural mesothelioma. This pattern is called pseudomesotheliomatous adenocarcinoma. Both patients were men, aged 62 and 71, with occupational asbestos exposure and a smoking history. In the first man the tumor lay along the pleura of the lower lung lobe and measured up to 6.5 cm. In the second it spread along the pleura of the entire right lung, and chemotherapy had almost no effect. Tissue staining showed lung adenocarcinoma markers in both tumors. The first tumor was also broadly positive for several markers usually seen in mesothelioma. Electron microscopy of that tumor showed short, sparse microvilli, which the authors took as supporting adenocarcinoma. Asbestos body counts were 331 per gram of dry lung tissue in the first case and 11 318 in the second. The authors concluded that electron microscopy can be decisive for diagnosis. They also said a low asbestos body count does not rule out occupational exposure. The asbestos fiber type was not reported.

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 of two autopsy cases, with a discussion of previously reported cases
• Who was studied: Two men, aged 62 (Case 1) and 71 (Case 2), treated at hospitals in Miyagi, Japan; both were smokers
• Exposure: Occupational asbestos exposure in both patients; fiber type, job and dose not stated
• Main results:
  • Case 1: the tumor ran along the pleura of the lower lung lobe and measured up to 6.5 cm in diameter; the patient died of respiratory failure 6 days after admission
  • Case 2: the tumor spread along the pleura of the entire right lung, with a lung lesion up to 3 cm in the middle lobe
  • Case 1: besides lung adenocarcinoma markers, the tumor cells broadly expressed markers frequently found in mesothelioma (calretinin, CK5/6, vimentin, thrombomodulin, HBME-1); D2-40 was not expressed
  • Case 2: the tumor was broadly positive for lung adenocarcinoma markers, and mesothelioma markers were mostly negative, although vimentin and thrombomodulin were detected
  • Case 1: electron microscopy showed short, sparsely distributed microvilli on the tumor cells
  • Case 1: 331 asbestos bodies per 1 g of dry lung tissue (none seen on routine or iron stains)
  • Case 2: 11 318 asbestos bodies per 1 g of dry lung tissue (none seen histologically)
  • The authors noted that more than 1000 bodies per gram of dry lung tissue is generally related to a high possibility of occupational exposure. They described the Case 2 count as significantly high and the Case 1 count as not significantly increased.
  • Case 2: the tumor grew rapidly and systemic chemotherapy had almost no effect; the patient died at 37 days after admission
• The authors' conclusion: The authors concluded that electron microscopy can be determinative for diagnosis because this tumor can show variable staining profiles. They also concluded that measuring asbestos bodies in such tumors may help clarify the relationship between asbestos exposure and tumor development.
• Limitations the authors state:
  • The authors stated that a lower asbestos body count cannot exclude occupational exposure to asbestos

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: Adenocarcinoma, Pseudomesotheliomatous Adenocarcinoma, Autopsy, Asbestos Exposure, Pleura, Diaphragm, Thyroid Transcription Factor-1 (TTF-1), Calretinin.

Related studies

• Comparative genetic analysis of a rare synchronous collision tumor composed of malignant pleural mesothelioma and primary pulmonary adenocarcinoma — T. Naka, Y. Hatanaka, et al. (2016)
• The forensic significance of pseudomesotheliomatous adenocarcinoma of the lung — J.M. Kennedy (2019)
• Pseudomesotheliomatous adenocarcinoma of the lung with rhabdoid features — J.H. Attems, F. Lintner (2001)
• Calretinin, thrombomodulin, CEA, and CD15: a useful combination of immunohistochemical markers for differentiating pleural epithelial mesothelioma from peripheral pulmonary adenocarcinoma — C.E. Comin, L. Novelli, et al. (2001)
• Utility of a CEA, CD15, calretinin, and CK5/6 panel for distinguishing between mesotheliomas and pulmonary adenocarcinomas in clinical practice — T. Mohammad, J. Garratt, et al. (2012)
• E-cadherin, E-selectin and vascular cell adhesion molecule: immunohistochemical markers for differentiation between mesothelioma and metastatic pulmonary adenocarcinoma? — A.M. Müller, A. Weichert, et al. (2002)

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