A Case of Localized Malignant Peritoneal Mesothelioma With Lung Cancer Detected by 18F-FDG PET/CT

Our plain-English summary of A Case of Localized Malignant Peritoneal Mesothelioma With Lung Cancer Detected by 18F-FDG PET/CT, by S. Kobayashi Shimizu, T. Okamura, K. Koyama, et al (Clinical Nuclear Medicine, 2020).

The study

• Authors: S. Kobayashi Shimizu, T. Okamura, K. Koyama, H. Seura, N. Nishida
• Journal: Clinical Nuclear Medicine
• Published: 2020;45(10):795-797
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A 62-year-old woman was referred for cough and lower abdominal pain. F-FDG PET/CT showed strong uptake not only in the left lung mass and hilar and mediastinal lymph nodes, but also a huge lower abdominal mass. All lesions were initially thought to be multiple metastases because bronchial biopsy of the lung mass showed poorly differentiated adenocarcinoma. However, the abdominal mass was found to be malignant peritoneal mesothelioma after surgical resection. It was difficult to diagnose this case correctly before resection because localized malignant peritoneal mesothelioma is rare.

In plain English

This case report, by doctors at a hospital in Osaka, Japan, described one 62-year-old woman with cough and lower abdominal pain. The article states she was never exposed to asbestos. Scans showed a 5-cm tumor in her left lung, swollen lymph nodes in the chest, a 10-cm tumor in the lower right abdomen, and a brain metastasis. An 18F-FDG PET/CT scan shows how strongly tissues absorb a radioactive sugar tracer. All these areas absorbed the tracer. The abdominal mass did so most strongly, above the scanner's measurement limit of 32.7. A lung biopsy showed poorly differentiated adenocarcinoma, a type of lung cancer, and the other lesions were first suspected to be its spread. The abdominal mass was surgically removed because it had stuck to the colon and could cause a blockage. Tissue examination confirmed epithelioid malignant peritoneal mesothelioma, and from its appearance the tumor was considered to be of the localized type. The authors concluded that diagnosis before surgery was difficult because of the lung cancer, the absence of abdominal fluid (ascites), and no abnormal tracer uptake elsewhere in the abdominal lining.

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 (an 'Interesting Image' report of a single patient)
• Who was studied: one 62-year-old woman with cough and abdominal pain, reported by doctors at Saiseikai Nakatsu Hospital, Osaka, Japan
• Exposure: No asbestos exposure: the article states the patient had no medical history and was never exposed to asbestos
• Main results:
  • In the patient, CT showed a 5-cm tumor with cavity and necrosis in the left upper lobe of the lung, swollen mediastinal and left hilar lymph nodes, and a 10-cm tumor with necrosis in the lower right abdomen
  • In the patient, contrast-enhanced MRI showed a brain metastasis in the right temporal lobe
  • In the patient, the PET/CT uptake value (SUVmax) was 21.7 for the lung mass, 3.2 for the mediastinal lymph node, 9.4 for the left hilar lymph node and 7.7 for the right temporal lobe mass
  • In the patient, the right lower abdominal mass had an SUVmax greater than 32.7, which was the scanner's upper measurement limit
  • Bronchial biopsy of the patient's lung tumor showed poorly differentiated adenocarcinoma, meaning the swollen lymph nodes were metastases. The lesions were at first suspected to be metastases from the lung cancer
  • The patient's abdominal mass was surgically removed because it had adhered to the colon and could cause obstruction
  • Pathology confirmed the patient's abdominal mass as epithelioid malignant peritoneal mesothelioma. Separately, it was morphologically considered to be the localized type
• The authors' conclusion: The authors concluded that diagnosis before surgery was difficult in this case because of the presence of lung cancer, the lack of ascites, and no abnormal FDG uptake in other parts of the peritoneum

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Lung Cancer, Mediastinal Lymph Nodes, Biopsy, Adenocarcinoma, Surgical Resection.

Related studies

• 18F-FDG Uptake of Localized Malignant Peritoneal Mesothelioma — E. Kodama, T. Kodama, et al. (2020)
• 18F-FDG-PET/CT of peritoneal tumors: a pictorial essay — J. Dubreuil, F. Giammarile, et al. (2017)
• Focal Peritoneal Mesothelioma Demonstrated on FDG PET/CT — J. Xiao, H. Yin, et al. (2019)
• The role of 18F-FDG-PET/ceCT in peritoneal mesothelioma — J. Dubreuil, F. Giammarile, et al. (2017)
• Whole-Body MRI: Comparison of Its Capability for TNM Staging of Malignant Pleural Mesothelioma With That of Coregistered PET/MRI, Integrated FDG PET/CT, and Conventional Imaging — Y. Ohno, M. Yui, et al. (2019)
• Present and future roles of FDG-PET/CT imaging in the management of malignant pleural mesothelioma — K. Kitajima, H. Doi, et al. (2016)

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