Rare diseases bullet 13: Non-neoplastic pulmonary lymphoid lesions

Pulmonary lymphoid lesions encompass a spectrum of inflammatory and reactive lesions that are often diYcult to diagnose since they are diYcult to diVerentiate from other reactive and neoplastic entities (box 1). Understanding these lymphoid lesions is complicated by the evolution of concepts, criteria, and terminology over the past few decades. This review will attempt to summarise a historical perspective on this subject and present the current concepts of pulmonary lymphoid lesions.