Pseudomesotheliomatous Carcinoma of the Lung with Morphological Characteristics of Signet Ring Cell Carcinoma: An Autopsy Case Report

Our plain-English summary of Pseudomesotheliomatous Carcinoma of the Lung with Morphological Characteristics of Signet Ring Cell Carcinoma: An Autopsy Case Report, by T. Hirakawa, T. Tanimoto, Y. Hattori, et al (Internal Medicine, 2024).

The study

• Authors: T. Hirakawa, T. Tanimoto, Y. Hattori, R. Katsura, S. Miyake, S. Fujita, S. Ueno, K. Masuda, T. Nishisaka, N. Ishikawa
• Journal: Internal Medicine
• Published: 2024;63(7):979-983
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

A 50-year-old woman presented with left pleural effusion. A pleural fluid cell-block specimen and longitudinal lymph node needle biopsy suggested signet ring cell carcinoma (SRCC). Although computed tomography showed a consolidation shadow in the left lower lobe, a left lung biopsy could not be performed. Upper gastrointestinal endoscopy revealed no malignancies. We administered carboplatin, pemetrexed, ipilimumab, and nivolumab for lung cancer; however, she died due to progressive respiratory failure. Pathological autopsy revealed that the left pleura was thickened as in mesothelioma, based on which pseudomesotheliomatous carcinoma of the lung (PMCL) was diagnosed. PMCLs exhibiting an SRCC morphology are rare.

In plain English

This Japanese case report described a 50-year-old woman with a dry cough and fluid around her left lung. She had no reported history of smoking or asbestos exposure. Her blood CA19-9, a tumor marker, was 29,724 U/mL (reference 0-37 U/mL). Cells in the pleural fluid, and biopsies of a chest lymph node and the uterine lining, showed signet ring cell carcinoma, a type of adenocarcinoma, with a stomach-like pattern. Stomach endoscopy and body scans found no primary tumor. She was treated for lung cancer with carboplatin, pemetrexed, ipilimumab and nivolumab. She died on day 37 after admission. At autopsy the left pleura was thickened as in mesothelioma. However, epithelial mesothelioma markers were negative, no findings suggested asbestos exposure, and a lung surfactant marker (PE-10) was focally positive, while the usual lung adenocarcinoma markers TTF-1 and napsin A were negative. This led to a diagnosis of pseudomesotheliomatous carcinoma of the lung. About 50% of the tumor cells were of the signet ring type. The authors stated that, to their knowledge, this was the first such case in which genetic abnormalities were examined.

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, with autopsy)
• Who was studied: one 50-year-old woman with dry cough and left pleural effusion, treated at Hiroshima Prefectural Hospital, Japan
• Exposure: No asbestos exposure: the patient had no history of smoking or asbestos exposure, and autopsy showed no findings suggesting asbestos exposure
• Main results:
  • The patient had no history of smoking or exposure to asbestos
  • The patient's serum CA19-9 was 29,724 U/mL (reference interval 0-37 U/mL)
  • The pleural fluid cell-block showed findings compatible with signet ring cell carcinoma
  • Upper gastrointestinal endoscopy, contrast-enhanced whole-body CT and MRI did not show a primary lesion
  • Subcarinal lymph node and endometrial biopsies showed signet ring cell carcinoma with gastric-type morphology similar to the cells in the pleural fluid
  • The tumor was negative for the EGFR mutation, ALK fusion gene, ROS1 fusion gene and BRAF V600E mutation
  • The patient received carboplatin, pemetrexed, ipilimumab and nivolumab
  • The patient died on day 37 after admission
  • At autopsy the left pleura was thickened as in mesothelioma, with tumor seeding in the right visceral pleura
  • The epithelial mesothelioma marker was negative
  • At autopsy the tumor was focally positive for PE-10 (a lung surfactant marker described as highly specific for pneumocytes) and negative for TTF-1 and napsin A, the markers commonly used to diagnose lung adenocarcinoma; these findings contributed to the diagnosis of pseudomesotheliomatous carcinoma of the lung
  • Approximately 50% of the tumor cells had a signet ring cell carcinoma component
  • Respiratory failure due to lymphangitis carcinomatosa and pulmonary tumor thrombotic microangiopathy (PTTM) was considered the direct cause of death
• The authors' conclusion: The authors stated that, to their knowledge, this is the first case report of pseudomesotheliomatous carcinoma of the lung with signet ring cell carcinoma features in which genetic abnormalities were examined
• Limitations the authors state:
  • Lung biopsy of the left lower lobe consolidation and colonoscopy could not be performed because the patient's breathing worsened
  • Comprehensive cancer genome profiling was not feasible because the patient's condition deteriorated rapidly; only single-gene tests were done

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: Pseudomesotheliomatous Adenocarcinoma, Carcinoma, Autopsy, Pleural Effusion, Needle Biopsy, Consolidation, Biopsy, Endoscopy.

Related studies

• Mesothelioma with signet-ring cell features: report of 23 cases — N.G. Ordóñez (2013)
• Signet ring cell mesothelioma; A diagnostic challenge — H. Wang, C. Herath (2019)
• "Signet-ring" cells--a caveat in the diagnosis of a diffuse peritoneal mesothelioma occurring in a lady presenting with recurrent ascites: an unusual case report — B. Rekhi, S. Pathuthara, et al. (2010)
• Pulmonary acantholytic squamous cell carcinoma with focal signet ring cell morphology mimicking malignant mesothelioma on fine needle aspiration cytology: a case report — S.E. Choi, H.S. Park (2016)
• Signet-ring cell appearance of atrophic fat cells — J.D. Gilbert, N.E.I. Langlois, et al. (2021)
• Pseudomesotheliomatous carcinoma of the pleura: an autopsy case of metastasis from a G-CSF-producing anaplastic carcinoma of the pancreas — Y. Hattori, K. Sentani, et al. (2018)

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