Localized malignant pleural mesothelioma mimicking an anterior mediastinal tumor

Our plain-English summary of Localized malignant pleural mesothelioma mimicking an anterior mediastinal tumor, by T. Hino, T. Kamitani, K. Sagiyama, et al (European Journal of Radiology Open, 2019).

The study

• Authors: T. Hino, T. Kamitani, K. Sagiyama, Y. Yamasaki, I. Okamoto, T. Tagawa, K. Ijichi, H. Yamamoto, H. Yabuuchi, H. Honda
• Journal: European Journal of Radiology Open
• Published: 2019;6:72-77
• Type of article: Case report
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Localized malignant pleural mesothelioma (LMPM) is an extremely rare tumor. We report the case of a 40-year-old Japanese male with an LMPM mimicking an anterior mediastinal tumor due to invasion to the anterior mediastinum, and we discuss mainly the differentiation of LMPM from an anterior mediastinal tumor. The present tumor had a long shape along the pleura, and LMPM could be one of the differential diagnoses.

In plain English

This is a case report of one patient with localized malignant pleural mesothelioma, a rare form that grows as a single defined mass rather than spreading diffusely along the pleura. A 40-year-old Japanese man had an abnormal shadow found on a chest X-ray at a routine check-up. CT showed a 5.4 cm multi-nodular mass mainly in the anterior mediastinum (the front of the chest). PET scanning showed high uptake in the tumor and no other lesions. A needle biopsy was read as suspicious for adenocarcinoma, and he was treated for thymic cancer with chemotherapy and radiation. The tumor did not shrink significantly. After the tumor was removed by surgery, pathologists confirmed malignant pleural mesothelioma of the biphasic type. The tumor came back locally after surgery, chemotherapy did not stop its growth, and he died 44 months after surgery. Looking back, the authors noted the tumor was long in shape along the right pleura. They concluded that this tumor type should be considered when a mediastinal mass has that shape. The article does not say whether the patient had been exposed to asbestos.

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 discussion of imaging features
• Who was studied: One 40-year-old Japanese man, referred to a hospital (authors' affiliation: Kyushu University, Fukuoka, Japan) after an abnormal chest radiograph at an annual check-up
• Exposure: Not reported. The article does not state whether this patient had any asbestos exposure. The asbestos figures in the discussion (20%–40% of cases) come from earlier published reports, not from this patient.
• Main results:
  • Contrast-enhanced CT in this patient showed a multi-nodular, heterogeneous mass 5.4 cm in maximum diameter, located mainly in the anterior mediastinum and broadly adjacent to the pleura and right lung.
  • FDG-PET showed abnormal uptake in the tumor. The text gives a maximum standardized uptake value of 9.66; the figure legend gives 9.88. No other lesion was seen at any site.
  • A CT-guided biopsy suggested adenocarcinoma. The patient was treated for thymic cancer with neoadjuvant chemoradiotherapy (40 Gy in 20 fractions, with carboplatin and paclitaxel, listed as CBDCA and PTX). The tumor did not shrink significantly.
  • At surgery the tumor had infiltrated the pericardium, a rib and the right lung. Pathology and immunohistochemistry confirmed malignant pleural mesothelioma with a biphasic (epithelioid and sarcomatous) pattern.
  • A small nodule appeared in the anterior mediastinum 12 months after resection and was considered local recurrence at 18 months. Chemotherapy (CDDP and PEM) did not stop its growth. Pleural dissemination followed, and the patient died 44 months after the original surgery.
  • Reviewed afterwards, the tumor was vertically long along the right pleura on curved multi-planar reconstructed CT images. The authors suspect this shape is atypical for mediastinal tumors.
• The authors' conclusion: The authors concluded that localized malignant pleural mesothelioma should be considered in the differential diagnosis of a mediastinal mass with a long shape along the pleura, and that multi-planar views might be useful for diagnosing it.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Mediastinum, Pleura.

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• An unusual isolated anterior mediastinal lesion — N. Quigley, L. Lang-Lazdunski, et al. (2022)
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