Imaging characteristics of pleural tumours

Mesotheliomas and Benign Mesothelial Tumors: Update on Pathologic and Imaging Findings

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A, and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A-, NF2-, and BAP1-altered mesotheliomas are under consideration. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Non-glandular findings on breast ultrasound. Part II: a pictorial review of chest wall lesions

The breast ultrasound (US) field-of-view (FOV) includes glandular parenchyma as well as tissues located anterior to and posterior to it, up to pleural line. For that, it is possible to incidentally identify lesions unrelated to breast parenchyma during screening or diagnostic US; sometimes a palpable lump may be the reason of the imaging exam. Furthermore, abnormality related to chest wall are easier and more accurate detected after mastectomy. Hence, radiologists should know the US appearance of lesions which may develop from all tissues present in this region and displayed in the US FOV, without focusing only on glandular abnormalities while performing the exam. This is the second of a two-part series on non-glandular breast lesions; in detail, part two provide an overview of US appearance, differential diagnosis, and pitfalls of chest wall lesions. They may have an infectious, traumatic, inflammatory etiology or be benign or malignant neoplasms. The US role in the assessment of chest wall abnormalities is limited, usually computed tomography and/or magnetic resonance are requested as second-level imaging exams to characterize and to assess better their relationship with surrounding structures because of larger and panoramic view. Finally, US could be useful to guide biopsy.

Pleural metastasis of pulmonary adenocarcinoma mimicking diffuse mesothelioma: A case report and literature study

Conditions on pleura cover a broad range of pathology ranging from benign to malignant, which may potentially carry a poor prognosis and lead to high morbidity and mortality. Radiology plays a pivotal role in the diagnosis of pleural malignancy; however, the diagnostic endeavor can be challenging because of overlapping radiological appearances of one condition to another. This case report presents a 61-year-old male with worsening chronic shortness of breath. Despite early imaging resulting in highly suggested mesothelioma, subsequent biopsy proved the malignancy to be pulmonary adenocarcinoma. The patient underwent Pemetrexed-Cisplatin protocol in accordance with the biopsy result, and follow-up imaging depicted a marked improvement of the pleural condition. This case is a prime example of the challenge radiologists have to face regarding pleural tumors and dictates the necessity of a specialized multidisciplinary team to improve the patient's outcome.

Tumor and tumorlike conditions of the pleura and juxtapleural region: review of imaging findings

Pleural lesions form a diagnostic challenge for the radiologist. Whereas lesions can be initially detected on chest radiographs, CT and MRI imaging are the imaging modalities of choice for further characterization. In a number of cases, imaging findings can be relatively specific. In general unfortunately, imaging findings are rather aspecific. Evolution and extrathoracic imaging findings are important clues toward the diagnosis.

Correlation between CT findings and thoracoscopic diagnosis in diffuse pleural disease

Objective:

Computed Tomography (CT) is considered part of the routine diagnostic workup for pleural malignancy. The definitive diagnosis of pleural malignancy depends upon histological confirmation by pleural biopsy. The aim of this study is to assess the sensitivity and specificity of CT, in view of the latest imaging technologies, in detecting pleural malignancy compared to definitive histology achieved via thoracoscopy (VATS).

Materials and methods:

We included in this retrospective study 90 patients (36 F, 54 M) with suspected pleural malignancy evaluated in our Institution with CT scan who received a definitive diagnosis after VATS biopsy. Unaware of histopathologic diagnoses CT scans were evaluated by a junior and two experts thoracic radiologist. Conclusions were reached by consensus.

Results:

We evaluated all CT signs suggestive for malignant pleural diseases: pleural thickening > 10 mm (Se 0,41 , Sp 0,79); nodular thickening (Se 0,86, Sp 0,75); circumferential thickening (Se 0,79, Sp 0,69); irregular pleural thickening (Se 0,77, Sp 0,91); mediastinal involvement (Se 0,88, Sp 0,64); costal involvement (Se 0,89, Sp 0,60); diaphragmatic involvement (Se 0,88, Sp 0,53). Furthermore, the diagnostic performance of additional CT features was evaluated: concomitant costal, mediastinal and diaphragmatic pleura lesions (Se 0,84, Sp 0,69); nodular/irregular thickening with mediastinal pleural involvement (Se 0,83, Sp 0,90); nodular/irregular thickening with diaphragmatic pleural involvement (Se 0,81, Sp 0,90).

Conclusions:

CT confirms its central role in the pleura malignancy. The high sensibility, respect to previous studies, especially in the presence of nodular pleural thickening, may lead to reconsider at least partly the diagnostic pathway of diffuse pleural disease, avoiding the use of VATS in patients not eligible for surgery, in favor of US or CT guided core biopsy. (www.actabiomedica.com)

Biphasic chest wall synovial sarcoma with epithelial pleural effusion: a diagnostic challenge

Synovial sarcoma (SS) is a rare malignancy that most commonly involves the extremities and large joints. We describe a 67-year-old woman who presented with shortness of breath and flu-like symptoms, and a chest wall mass. On resection of the mass biphasic morphology of SS was noted, as well as confirmatory immunostains including TLE1 and bcl2. An SS18/SSX2 fusion transcript was detected by reverse transcriptase-DNA amplification. A year later, following chemotherapy, the patient developed a right-sided pleural effusion. Cytological examination of the fluid showed an epithelial population forming clusters and groups. TLE1 was positive, as well as fluorescent in situ hybridization analysis for the SS18/SSX2 fusion transcript. SS can be a challenging diagnosis in fluid-filled cavities, when the epithelial component predominates and its original biphasic quality is not seen. We discuss the diagnostic challenges of monophasic and biphasic SS, and updates to ancillary testing.

Pleural tumours and tumour-like lesions

There are various neoplasms and tumour-like conditions of the pleura. Mesothelioma is perhaps the most widely recognised; however, there are many others that are more common and should be considered. Understanding the similarities and differences can be helpful in managing the patient with a newly found pleural lesion. We will discuss clinical symptoms at presentation and describe the imaging findings associated with these tumours, starting with conventional radiology, and correlating with computed tomography and combined positron-emission tomography (PET)/computed tomography (CT). Finally, imaging characteristics that help differentiation between the benign and malignant varieties will be reviewed.