pulmonary disorders
Idiopathic Pulmonary Fibrosis
Pathology of Idiopathic Pulmonary Fibrosis
The key histologic findings of idiopathic pulmonary fibrosis are subpleural fibrosis with sites of fibroblast proliferation (fibroblast foci) and dense scarring, alternating with areas of normal lung tissue (heterogeneity). Scattered interstitial inflammation occurs with lymphocyte, plasma cell, and histiocyte infiltration. Cystic abnormality (honeycombing) occurs in all patients and increases with advanced disease. A similar histologic pattern uncommonly occurs in cases of interstitial lung diseases of known etiology (see table). 