Lymphoid Interstitial Pneumonia and Other Benign Lymphoid Disorders.

Benign pulmonary lymphoid disorders include a variety of rare lymphoid abnormalities characterized by a polyclonal lymphoid infiltrate with differing histopathologic patterns and clinicoradiologic features that may overlap. Histological examination is essential to reach a correct diagnosis and to exclude alternative causes, although this task can at times prove difficult. Further studies and clinical trials are needed to provide additional insights on pathogenesis and to guide the therapeutic management of these disorders. The purpose of this article is to review the histopathological, epidemiological, and clinicoradiologic features of several benign pulmonary lymphoid disorders, including lymphoid interstitial pneumonia, follicular bronchiolitis, nodular lymphoid hyperplasia (pulmonary pseudolymphoma), inflammatory pseudotumor, immunoglobulin G4-related disease, Castleman disease, posttransplantation lymphoproliferative disease, and drug-induced lymphoid disorders.