A Rare Case of Sarcomatoid-Type Localized Pleural Mesothelioma Derived From Visceral Pleura

Our plain-English summary of A Rare Case of Sarcomatoid-Type Localized Pleural Mesothelioma Derived From Visceral Pleura, by T. Kosaka, S. Nakazawa, R. Ushikubo, et al (Curēus, 2025).

The study

• Authors: T. Kosaka, S. Nakazawa, R. Ushikubo, T. Ibe, K. Shirabe
• Journal: Curēus
• Published: 2025;17(3):e81473
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

A man in his 80s presented with shortness of breath. Chest CT scan showed pleural effusion and a mass in the right lower lobe. He had high inflammatory reaction and was diagnosed as having pulmonary suppuration with empyema. After three weeks of antibiotic treatment, the lesion grew and he was referred to our department for surgical intervention. A complete resection of the right lower lobe was planned to control infection. Intraoperative findings showed that the lower lobe became a large mass and was judged unresectable. The procedure was converted to drainage of the abscess cavity. Pathological examination, combined with clinical and radiological findings, led to the diagnosis of localized sarcoma-type malignant pleural mesothelioma. Localized malignant pleural mesothelioma is a rare disease and most cases have been reported as epithelial type, deriving from the parietal pleura. Our case is quite rare because it was a sarcoma-type, deriving from the visceral pleura.

Copyright © 2025, Kosaka et al.

In plain English

This was a case report of one man in his 80s treated in Gunma, Japan. He had been short of breath for a week, was a current smoker (90 pack-years), and had never been exposed to asbestos, the authors reported. A chest CT showed fluid around the lung and a 60x50x80 mm mass in the right lower lobe. Doctors first diagnosed a lung infection with pus in the chest cavity (pulmonary suppuration with empyema). With no improvement after three weeks of antibiotics, he was referred for surgery; a CT four weeks after the first showed the mass had grown to 110x110x150 mm. Surgeons judged the lobe could not be removed and drained the abscess cavity instead. Examination of tissue taken during surgery led to a diagnosis of sarcomatoid-type localized pleural mesothelioma. The authors judged that it arose from the visceral pleura, the lining that covers the lung. The mass kept growing, and the patient died two months after the operation. The authors concluded that this tumor type should be considered when a rapidly growing mass is seen in the chest.

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 (one patient)
• Who was studied: One man in his 80s with hypertension, diabetes and chronic obstructive pulmonary disease, referred to the Department of Thoracic Surgery, NHO Takasaki General Medical Center, Gunma, Japan; dates of care not stated
• Exposure: No asbestos exposure reported; the patient was a current smoker with 90 pack-years
• Main results:
  • The first chest CT showed a moderate amount of pleural effusion and a 60x50x80 mm mass in the right lower lobe. The patient was initially diagnosed with pulmonary suppuration with empyema and treated with antibiotics.
  • With no improvement after three weeks of antibiotic treatment, the patient was referred for surgery.
  • Four weeks after the first CT, the lesion had grown to 110x110x150 mm, with fluid inside the mass.
  • The planned removal of the right lower lobe was judged too difficult, so the operation was changed to drainage of the abscess cavity.
  • On pathology, 70% of tumor cells were positive for Ki67, and the cells stained positive for keratin AE1/AE3, keratin CAM5.2 and CD99. The tumor was diagnosed as sarcomatoid-type pleural mesothelioma.
  • The tumor was judged to arise from the visceral pleura because surgery showed no invasion of the parietal pleura. It was judged solitary because thoracic and upper abdominal CT showed no other lesions.
  • After the operation the mass continued to grow. Chemotherapy was not given because of worsening performance status, and the patient died two months after the operation.
• The authors' conclusion: The authors concluded that sarcomatoid-type localized pleural mesothelioma should be considered as a possible diagnosis when a rapidly growing mass is seen in the chest cavity. They noted that in this case, inflammation and pleural effusion from infection inside the tumor made it hard to tell apart from pulmonary suppuration before the operation.

Topics

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Pleural Mesothelioma, Visceral Pleura, CT Scan, Pleural Effusion, Empyema, Unresectable, Sarcoma.

Related studies

• Genome-wide profile of pleural mesothelioma versus parietal and visceral pleura: the emerging gene portrait of the mesothelioma phenotype — O.D. Røe, E. Anderssen, et al. (2009)
• Early response of the visceral pleura following asbestos exposure: an ultrastructural study — R.F. Dodson, J.O. Ford (1985)
• Inflammation of the visceral pleura, a nonspecific asbestos-related pleural reaction: chest radiograph and computed tomograph correlation — A. Solomon, A.H. Rubin, et al. (1991)
• Independent lung ventilation using a piston-driven anesthesia machine to ventilate the affected lung during resection of the visceral pleura for malignant pleural mesothelioma: A case series — T. Kida, T. Kobashi, et al. (2021)
• Localized malignant pleural sarcomatoid mesothelioma misdiagnosed as benign localized fibrous tumor — K.C. Kim, H.P. Vo (2016)
• Sarcomatoid malignant peritoneal mesothelioma presenting as a localized mesenteric tumor with no previous asbestos exposure — Y.A. Notue, U.I. Mbessoh, et al. (2020)

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