Search

Asbestos-related neoplastic and nonneoplastic diseases of the lungs and pleura range from pleural effusion and pleural plaques to lung cancer and malignant mesothelioma. Pleural effusions are typically hemorrhagic exudates of mixed cellularity but do not typically contain asbestos bodies. The classic distribution of pleural plaques seen on chest radiographs is the posterolateral chest wall between the seventh and tenth ribs, lateral chest wall between the sixth and ninth ribs, the dome of the diaphragm, and the mediastinal pleura. Computed tomographic (CT) findings support this distribution but also show anterior and paravertebral plaques not well shown at chest radiography. Imaging features of diffuse pleural thickening include a continuous sheet, often involving the costophrenic angles and apices, that rarely calcifies. The typical CT features of round atelectasis are of a round or oval mass that abuts the pleura, a "comet tail" of bronchovascular structures going into the mass, and thickening of the adjacent pleura. Features of asbestosis on chest radiographs include ground-glass opacification, small nodular opacities, "shaggy" cardiac silhouette, and ill-defined diaphragmatic contours. CT, however, is more sensitive in their detection. Chest radiography in patients with malignant mesothelioma may show an effusion, pleural thickening, and as the tumor progresses, a more lobulated outline. CT can help identify the disease in its early stages. Asbestos-related cancers can occur anywhere in the lungs. Recognition of the clinical, radiologic, and pathologic features of these diseases will be important for some years to come.

Background: Three cases of diffuse malignant vascular tumours of the pleura are described which mimicked malignant mesothelioma clinically and pathologically (so called "pseudomesothelioma"). All had occupational histories of exposure to asbestos. The relationship of these tumours to mesothelioma and asbestos exposure is discussed., Methods: To examine the histogenetic relationship between mesothelioma and these three tumours an immunohistochemical analysis of vascular marker (CD31, CD34, and Von Willebrand factor) expression was undertaken in 92 cases of pleural mesothelioma, in addition to these three tumours. Electron microscopic fibre analysis of lung tissue was performed on each of the three cases to assess asbestos fibre content., Results: Diffuse pleural epithelioid haemangioendotheliomas may closely resemble malignant mesothelioma clinically and pathologically but, of the 92 pleural mesotheliomas tested, none showed expression of CD31, CD34, and Von Willebrand factor. Although all three cases had claimed exposure to asbestos, ferruginous bodies typical of asbestos were only seen by light microscopy in case 2, and only in this subject was the asbestos fibre content raised in comparison with the range seen in a non-exposed background population. The latent period in the pleural epithelioid haemangioendotheliomas ranged from 18 to 60 years., Conclusions: Endothelial differentiation does not appear to occur in mesothelioma and therefore should be clearly separated from it. No definite association between pleural epithelioid haemangioendothelioma and exposure to asbestos can be made from this small series but further investigation is warranted.

Aims: The clinicopathological, immunohistochemical and aetiological aspects, with respect to asbestos, of seven primary gonadal mesotheliomas (three intratesticular, four ovarian) are described and compared. These tumours are extremely rare, poorly described and the knowledge of their natural history is very limited., Methods and Results: The cases were collated from the UK Health and Safety Executive Mesothelioma Register over a 24-year period (1968-91). Primary mesotheliomas of the tunica vaginalis and ovary comprised 0. 09% (10 cases) and 0.03% (three cases) of mesothelioma deaths, respectively. No primary intratesticular (non-tunica vaginalis) malignant mesotheliomas have been described. In this study, we present seven (three intratesticular, four ovarian) primary malignant gonadal mesotheliomas. In both genders the tumours show a similar age distribution (with median onset in the sixth decade), a similar association with asbestos (in approximately 50% cases), a diverse histological spectrum (with predominantly tubulopapillary epithelial subtype tumours) and an immunophenotype that is comparable with malignant pleural and peritoneal mesothelioma. The clinical course appears variable (mean, 26 months; range, 9-50 months). All tumours in the study presented as localized masses and their prognosis appeared more favourable than that of diffuse pleural and peritoneal cases., Conclusions: An awareness of the existence of these rare forms of malignant mesothelioma is important to prevent misdiagnosis. Immunohistochemistry has an important role in confirmation of the diagnosis. The accurate diagnosis of primary gonadal mesothelioma has potentially important medicolegal compensation considerations as a significant proportion of these cases are associated with asbestos.

Summary: The pleural space is a rare site of primary non-Hodgkin's lymphoma. Cases have been linked to chronic pleural inflammation often secondary to tuberculosis. We report a case of large B cell lymphoma of the pleural cavity occurring in an immunocompetent patient with no history of tuberculosis or suppurative lung disease presenting with radiological features consistent with pleural mesothelioma. This case highlights the important diagnostic pitfalls in the diagnosis of suspected mesothelioma. We conclude that in all such cases a definitive histological diagnosis should always be sought. [Copyright &y& Elsevier]