The forensic significance of pseudomesotheliomatous adenocarcinoma of the lung

Our plain-English summary of The forensic significance of pseudomesotheliomatous adenocarcinoma of the lung, by J.M. Kennedy (Forensic Science, Medicine, and Pathology, 2019).

The study

• Author: J.M. Kennedy
• Journal: Forensic Science, Medicine, and Pathology
• Published: 2019;15(3):458-462
• Type of article: Case report
• Read it: PubMed · Publisher

Abstract

Pseudomesotheliomatous carcinomas (PMC) are rare tumors that clinically, macroscopically, and sometimes histologically resemble malignant pleural mesotheliomas. We report a case of a 91 year woman who was found to have diffuse nodular pleural thickening and a lung mass during a workup for persistent cough. She declined rapidly and died before a histologic diagnosis could be made. Postmortem examination revealed a tumor that diffusely involved the pleural surface with local extension into the chest wall, pericardium, and diaphragm along with a concurrent lung mass. Histologic examination showed poorly-differentiated cells predominantly arranged in sheets, cords, and nests with focal glandular differentiation. An immunohistochemical panel of calretinin, WT1, BEREP4, MOC31, and TTF1 confirmed the diagnosis of primary lung adenocarcinoma. The macroscopic, histologic, and immunohistochemical features used to distinguish metastatic and primary lung adenocarcinoma from epithelioid malignant mesothelioma are discussed. The distinction of malignant mesothelioma from pseudomesotheliomatous carcinoma is important for medicolegal reasons regarding asbestos related compensation claims.

In plain English

This article is a case report describing one patient, written by a pathologist at the University of Michigan. A 91-year-old woman with a 35-year smoking history and no reported occupational exposures went to the emergency room with a cough that had lasted one month. A CT scan showed a 6 cm mass in her lower right lung and nodular thickening over the entire pleura, the lining around the lungs. She was readmitted with pneumonia, sepsis and respiratory failure and died 11 days later, before a biopsy could be done. Two pleural fluid samples showed no cancer cells. The autopsy was limited to the chest. It found tumor coating the inside of the chest and extending into the chest wall, pericardium and diaphragm, connected to a 4.5 cm lung mass. Microscope and marker-staining (immunohistochemistry) results supported primary lung adenocarcinoma rather than malignant mesothelioma. The author concluded that forensic pathologists should recognize this tumor, which can look like mesothelioma, to avoid misdiagnosis. The author noted that a misdiagnosis may affect asbestos compensation claims.

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 autopsy case) with discussion of diagnostic features
• Who was studied: one 91-year-old woman, seen at an emergency room and examined at autopsy; author affiliated with University of Michigan, USA
• Exposure: 35-year smoking history; no reported occupational exposures (no asbestos exposure was described or measured)
• Main results:
  • CT scan showed a 6 cm lung mass in the posterior basal right lower lobe and nodular pleural thickening involving the entire pleural surface
  • Two pleural fluid samples showed no malignant cells
  • The patient died 11 days after readmission, before a histologic diagnosis was made
  • At autopsy, tumor extended locally into the chest wall, pericardium and diaphragm
  • At autopsy, a 4.5 cm mass in the right lower lobe was continuous with the tumor on the pleura and chest wall
  • Immunohistochemistry was positive for TTF-1, MOC31 and BEREP4 and negative for p63, WT1 and calretinin, supporting primary lung adenocarcinoma with diffuse pleural involvement
• The authors' conclusion: The author concluded that forensic pathologists should recognize pseudomesotheliomatous adenocarcinoma to avoid misdiagnosing it as malignant mesothelioma, because misdiagnosis may have medicolegal consequences related to asbestos compensation claims
• Limitations the authors state:
  • The autopsy was limited to the chest, so spread of disease beyond the chest could not be assessed

Topics

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

Medical terms in this study, explained in our Lexicon: Pseudomesotheliomatous Adenocarcinoma, Pleural Mesothelioma, Pleural Thickening, Pericardium, Diaphragm, Calretinin, Lung Adenocarcinoma, Epithelioid.

Related studies

• Case reports of primary pulmonary adenocarcinoma with pleural spread: so-called pseudomesotheliomatous adenocarcinoma — R. Saito, A. Kasajima, et al. (2012)
• Pseudomesotheliomatous adenocarcinoma of the lung with rhabdoid features — J.H. Attems, F. Lintner (2001)
• Local recurrence of lung adenocarcinoma 10 years after left upper lobectomy resembling pseudomesotheliomatous adenocarcinoma: a case report — J. Okamoto, H. Kubokura, et al. (2014)
• Cytological differential diagnosis among adenocarcinoma, epithelial mesothelioma, and reactive mesothelial cells in serous effusions by immunocytochemistry — X.Y. Su, G.D. Li, et al. (2011)
• The diagnostic utility of D2-40, calretinin, CK5/6, desmin and MOC-31 in the differentiation of mesothelioma from adenocarcinoma in pleural effusion cytology — T.S. Hyun, M. Barnes, et al. (2012)
• Diagnostic efficacy of electron microscopy and pleural effusion cytology for the distinction of pleural mesothelioma and lung adenocarcinoma — H. Domínguez-Malagón, A.M. Cano-Valdez, et al. (2016)

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