Coalescent pleural malignant mesothelioma and adenocarcinoma of the lung, involving only minor asbestos exposure

Our plain-English summary of Coalescent pleural malignant mesothelioma and adenocarcinoma of the lung, involving only minor asbestos exposure, by T. Tsuzuki, H. Ninomiya, Y. Natori, et al (Pathology International, 2008).

The study

• Authors: T. Tsuzuki, H. Ninomiya, Y. Natori, Y. Ishikawa
• Journal: Pathology International
• Published: 2008;58(7):451-5
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Coexistence of pulmonary adenocarcinoma and pleural malignant mesothelioma is extremely rare, although both are asbestos-related. Herein is presented a rare case of coalescent lung tumor made up of a malignant mesothelioma and a pulmonary adenocarcinoma in a 62-year-old Japanese man, a high-school teacher with only minor asbestos exposure. Preoperative diagnosis of adenocarcinoma was made on transbronchial biopsy. At surgery, multiple small white nodules were observed on the parietal pleural surface, opposite to the lung tumor. They were confirmed to be malignant mesothelioma on histopathology of paraffin section. The pulmonary tumor mass itself consisted of two distinct portions. The major part contained papillary proliferation of hobnail and columnar cells. Peripherally, neoplastic cells grew in a lepidic fashion and micropapillary growth was also detected. The other component featured tubular structures. The former was positive for adenocarcinoma markers such as CEA, Ber-EP4, PE-10, thyroid transcription factor-1 and Napsin A, and negative for mesothelial markers including calretinin, D2-40, WT-1 and HBME, while the latter was the opposite, resulting in a diagnosis of coalescing malignant mesothelioma and adenocarcinoma. The panel of antibodies used for immunohistochemistry was useful to distinguish the two different components in the one tumor.

In plain English

This case report described a 62-year-old Japanese man, a high school teacher, whose routine chest X-ray showed a shadow in the lung. The report's clinical history recorded no smoking and no apparent asbestos exposure; the article's title calls the exposure minor. A biopsy before surgery showed lung adenocarcinoma. During surgery, small white nodules were found on the pleura, and samples from the parietal pleura (the chest-wall lining) showed malignant mesothelioma. The lung tumor itself had two parts. The larger part stained like lung adenocarcinoma. The other part stained with mesothelial markers such as calretinin and was diagnosed as malignant mesothelioma, epithelioid type. Lung tissue contained 94 asbestos fibers per gram of dry lung. The authors said this indicated apparent lack of asbestos exposure, while noting that exposure to chrysotile could not be excluded. The patient died of respiratory failure 26 months after surgery, and no autopsy was done. The authors concluded that detailed immunohistochemistry (staining tissue for marker proteins) helped clarify the origin and distribution of the two tumor components.

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 62-year-old Japanese man, a high school teacher, referred for an abnormal shadow on a routine chest radiograph
• Exposure: No smoking history and no apparent asbestos exposure in the history (the title describes exposure as minor). Lung tissue asbestos count was 94 fibers per 1 g of dry lung, which the authors described as much lower than levels for suspected occupational exposure (1000 to 5000).
• Main results:
  • Three samples from nodules on the parietal pleura had the features of malignant mesothelioma.
  • In the lung tumor, the larger ('speckled') part was positive for adenocarcinoma markers (CEA, Ber-EP4, PE-10, Napsin-A) and negative for mesothelial markers (calretinin, D2-40, WT-1, HBME-1). It was diagnosed as papillary adenocarcinoma.
  • The other ('solid') part of the lung tumor stained with calretinin, indicating mesothelial origin, and extended beyond the elastic layers of the visceral pleura. It was diagnosed as malignant mesothelioma, epithelioid type.
  • Lymphatic invasion and lymph node involvement were observed in the lung tumor.
  • The asbestos concentration in the patient's lung tissue was 94 fibers per 1 g of dry lung tissue, counted by a digestion method with a light microscope.
  • One year after surgery, malignant cells suspected to be of mesothelial origin were found in pleural fluid. Two years after surgery, a brain lesion developed and serum CEA rose to 204.2 ng/mL.
  • The patient died of respiratory failure 26 months after surgery. No autopsy was performed.
• The authors' conclusion: The authors concluded that this was an extraordinarily rare collision of malignant mesothelioma and lung adenocarcinoma, and that detailed immunohistochemistry was useful to clarify the origin and distribution of the two components. They interpreted the asbestos count as indicating apparent lack of asbestos exposure.
• Limitations the authors state:
  • The authors said it is debatable to compare a fiber count from their own laboratory with the values in the Helsinki Criteria.
  • The authors said exposure to chrysotile asbestos could not be excluded, because chrysotile may be broken down by lung cells and escape measurement.

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: Mesothelioma, Adenocarcinoma, Asbestos Exposure, Biopsy, Histopathology, Columnar Cell, Micropapillary, Ber-EP4.

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• Benign multicystic mesothelioma with concurrent colonic adenocarcinoma: a report of two cases — A. Husain, M. Ozdemirli (2012)
• A Case of Solitary Well-Differentiated Papillary Mesothelioma with Invasive Foci in the Pleura — S. Shimizu, H.E. Yoon, et al. (2017)
• Simultaneous occurrence of a rectal carcinoma and a diffuse well differentiated papillary mesothelioma of the peritoneum — G.R. Jatzko, J. Jester (1997)

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