Sarcomatoid carcinoma (carcinosarcoma) of the lung mimics malignant pleural mesothelioma on 18F-FDG PET/CT: a report of 2 cases

Our plain-English summary of Sarcomatoid carcinoma (carcinosarcoma) of the lung mimics malignant pleural mesothelioma on 18F-FDG PET/CT: a report of 2 cases, by A. Ciarallo, W. Makis, J.A. Novales-Diaz, et al (Clinical Nuclear Medicine, 2012).

The study

• Authors: A. Ciarallo, W. Makis, J.A. Novales-Diaz, R. Lisbona
• Journal: Clinical Nuclear Medicine
• Published: 2012;37(4):416-9
• Type of article: Case report
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Sarcomatoid carcinomas of the lung account for less than 0.4% of all lung tumors, and they are a heterogeneous group of non–small-cell lung carcinomas containing a sarcoma or sarcoma-like component. They have a poor prognosis, with an overall 5-year survival of 25% compared with 45% for other types of non–small-cell lung carcinomas. The literature on the use of 18F-FDG PET/CT to stage these tumors is very limited, and their PET/CT imaging characteristics have not been previously described. We report on 2 cases of sarcomatoid carcinoma that resembled malignant pleural mesothelioma on 18F-FDG PET/CT and were correctly staged.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This article reported two patients whose lung cancers looked like malignant pleural mesothelioma on 18F-FDG PET/CT scans, which show where tissues take up a sugar tracer. The first, a 79-year-old man, had a remote history of asbestos exposure, with no details given. His scan showed several masses along the lining of the right lung. One measured 7 by 5 cm and invaded the spine, another invaded the ribs, and there was a small lesion in a lower-back vertebra. Mesothelioma was strongly suspected, but a biopsy showed sarcomatoid carcinoma of the lung. He was judged inoperable and received palliative chemotherapy. The second was a 47-year-old man with a 30 pack-year smoking history. His scan showed a 12 cm chest wall mass extending through the ribcage, with spots in nearby lymph nodes. The authors concluded that this lung cancer can mimic malignant pleural mesothelioma on PET/CT and should be considered among possible diagnoses for malignant pleural diseases that take up the tracer. Because it covers only two patients, the report describes what happened to them, not how often this occurs.

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 (2 cases)
• Who was studied: Two men: a 79-year-old with a remote history of asbestos exposure (case 1) and a 47-year-old with a 30 pack-year smoking history (case 2). The article does not say where or when they were seen.
• Exposure: Case 1 had a remote history of asbestos exposure, with no fiber type, job, or amount given. Case 2 had a smoking history of 30 pack-years, and no asbestos exposure was mentioned for him. Both underwent 18F-FDG PET/CT imaging.
• Main results:
  • Case 1: PET/CT showed multiple pleural-based masses. One at the lung apex measured 7 by 5 cm (SUVmax 16.4) and invaded the thoracic vertebrae and upper back soft tissue. Another involved the right lateral pleura (SUVmax 11.5) and invaded ribs. There was also a small lesion in L3. Malignant pleural mesothelioma was strongly suspected.
  • Case 1: biopsy of the right lateral pleura showed sarcomatoid carcinoma of the lung. Staining was positive for CAM5.2, AE1/3 and CK7, and negative for S100, CK20, CK5/6, calretinin and TTF1.
  • Case 1: the patient was considered inoperable based on the PET/CT results and received palliative chemotherapy.
  • Case 2: PET/CT showed a large necrotic anterior chest wall mass, 12 cm in maximum diameter, extending through the ribcage (SUVmax 10.9). It also showed multiple foci in the right internal mammary lymph node chain, the largest 3 cm (SUVmax 6.4).
  • The authors stated that in both cases PET/CT detected local lymph node and distant metastases.
• The authors' conclusion: The authors concluded that in both cases the primary tumors mimicked malignant pleural mesothelioma. They said sarcomatoid carcinoma should be added to the differential diagnosis of FDG-avid malignant pleural diseases.

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: Sarcomatoid, Carcinoma, Pleural Mesothelioma, Sarcoma, Prognosis.

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