Pathologic Findings and Prognosis in a Large Prospective Cohort of Chronic Hypersensitivity Pneumonitis

Histopathologic patterns of c-NSIP and PI-PFG had a better transplant-free survival than did patterns of UIP, f-NSIP, and BF. The presence of fibroblast foci or dense collagen fibrosis correlated with progression to death or lung transplantation. Identification of fibroblast foci on biopsy samples, regardless of the underlying histopathologic pattern, may be a clinically useful predictor of survival in patients with HP.