History: 60 year old male with shortness of breath. 

Pleural plaques can be seen in numerous disease entities, and are most commonly seen in cases of prior asbestos exposure, as in this case. Other possibilities include prior empyema, hemothorax, or pleural effusion. Plaques can be mimicked by extrapleural fat. Pleural malignancies are an additional consideration, as plaques can be seen with mesothelioma and pleural metastases. Finally, pleurodesis can cause this appearance.

Plaques have been commonly described with thickened and nodular outlines, referred to as the Holly Leaf Sign.