Imaging of pleural masses: which to choose?

Our plain-English summary of Imaging of pleural masses: which to choose?, by A.S. Bruns, J.G. Mastronarde (Respiratory Medicine, 2008).

The study

• Authors: A.S. Bruns, J.G. Mastronarde
• Journal: Respiratory Medicine
• Published: 2008;102(3):328-31
• Type of article: Case report, Review
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The differential diagnosis of pleural masses is limited. Asbestos-related disease and invasive bronchogenic carcinoma make up the majority of cases. The diagnostic yield of biopsies is low, and invasive procedures are often required to achieve diagnosis. A variety of imaging techniques are available to help differentiate between benign and malignant disease to help discern which patients to biopsy. While computed tomography has a relatively good sensitivity and specificity, magnetic resonance imaging (MRI) and positron emission tomography (PET) both appear to have higher accuracy. MRI has the added benefit of being an excellent aid in determining surgical resectability of tumors. MRI and PET are limited, however, by their cost and availability in certain regions.

In plain English

This article was a teaching review of imaging tests used to evaluate masses in the pleura, the lining around the lungs. It opened with one patient, a 68-year-old woman whose chest X-ray revealed a possible right lower-lobe lung mass, after which a chest CT was performed. A PET scan showed the mass to be hypermetabolic, with a standardized uptake value of 7.7. Her biopsy suggested a nerve-based tumor. At surgery the mass was found to arise from an intercostal nerve in the posterior mediastinum, and it was a schwannoma. The authors then summarized earlier studies by others. Citing other sources, they wrote that pleural plaques are found in 20–60% of asbestos-exposed workers and are the most common cause of pleural masses. In the studies reviewed, chest X-rays were described as poor at telling benign from malignant disease. CT was described as better, and MRI and PET as appearing more accurate. The authors concluded that imaging beyond X-ray is needed, but that further research is required to decide which test should come next before biopsy.

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: Review (educational article on imaging of pleural masses), introduced by a single case presentation
• Who was studied: One patient, a 68-year-old woman with diabetes and hypertension, seen at the authors' outpatient pulmonary clinic (The Ohio State University Medical Center, Columbus, USA). The rest of the article reviews published imaging studies of patients with pleural disease.
• Exposure: No asbestos exposure was studied, and none is reported for the case patient. Asbestos-related pleural disease, citing other sources, is mentioned as the most common cause of pleural masses. The 'exposures' compared are imaging methods: chest radiography, CT, MRI, ultrasound and PET.
• Main results:
  • Case patient: a chest X-ray revealed a possible right lower-lobe lung mass, and a chest CT was then performed.
  • Case patient: PET showed the mass to be hypermetabolic, with a standardized uptake value of 7.7.
  • Case patient: at surgery the mass arose from the intercostal nerve between the fifth and sixth ribs in the posterior mediastinum, and frozen sections showed a schwannoma. The authors noted that posterior mediastinal masses can masquerade as pleural masses, depending on the imaging chosen.
  • Reported from cited sources, not this study: pleural plaques are found in 20–60% of asbestos-exposed workers and are the most common cause of pleural masses.
  • Reported from a cited study: when evaluating for asbestos-related disease, radiography has a sensitivity of only 13–53%.
  • Reported from a cited study (Hierholzer et al., 42 patients): CT features were present in 25 of 27 malignant cases versus 2 of 15 benign cases, a sensitivity of 93% and specificity of 87% for malignant disease. The features were mediastinal pleural involvement, nodularity, contour irregularity, and infiltration of the chest wall or diaphragm.
  • Reported from a cited study (Falaschi et al., 34 patients): on MRI, high signal intensity on T2-weighted images had a specificity of 87%, a sensitivity of 100% and a negative predictive value of 100% for malignant lesions.
  • Reported from a cited study (25 patients, 16 malignant and 9 benign): PET correctly detected all cases of malignancy and 7 of the 9 benign cases.
  • Reported from a cited study (92 patients, all with non-small cell lung cancer): PET had a sensitivity of 100%, specificity of 71%, PPV of 63% and NPV of 100% for pleural malignancy. Combined with CT, specificity rose to 76% and PPV to 67%.
• The authors' conclusion: The authors concluded that radiography is usually a first step, but further imaging beyond it is required. They added that further research is needed to determine which imaging modality, or combination of modalities, is the most useful next step before biopsy.

Topics

Medical terms in this study, explained in our Lexicon: Differential Diagnosis, Bronchogenic Carcinoma, Biopsy.

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