Multiple Pleural Plaques

Abstract

Abstract The radiological features of 12 cases of multiple pleural plaques are presented. Some of their chest radiographs show, instead of the usual holly leaf calcified plaque, a multinodular type of calcification which may be confused with tuberculosis. Only part of a plaque may be calcified, and some plaques show only a soft tissue density. Serial films of one case show only soft tissue density plaques at one stage, but subsequently linear calcification develops. In another case with no apparent calcification a pre-operative radiological diagnosis of multiple pleural plaques such as occur in asbestosis was confirmed at thoracotomy performed for an apical tumour. This is believed to be the first recorded pre-operative diagnosis in a case showing soft tissue density plaques only. The faintness of such lesions helps to distinguish them from intra-pulmonary nodules; this may be called the “faint shadow sign”. The relationship to asbestos inhalation and the significance of the plaques are discussed.