Sarcoidosis is an inflammatory disease characterised by the presence of noncaseating granulomas.The granuloma is the pathologic hallmark of sarcoidosis. Desquamative interstitial pneumonia Is characterised by extensive accumulation of macrophages in intraalveolar spaces with minimal interstitial fibrosis.Granulomas are not formed in usual interstitial pneumonitis and diffuse alveolar damage. Reference:Harrison's Medicine-18th edition,page no:2805,2806,2167.