Farmer's lung: Report of two cases in which lung biopsies were performed

Two cases of farmer's lung are reported, with a discussion of the histopathologic changes seen in lung biopsy specimens. Farmer's lung is a distinct clinical entity characterized by severe dyspnea and varying degrees of fever, chills, cyanosis and prostration. It is closely related to the inhalation of moldy hay or silage although the ultimate etiologic agent is not known. The occurrence of two cases in Western Pennsylvania suggests that the disease is probably more common in this country than is indicated in the literature. The essential histologie features are granulomatous pneumonitis and bronchiolitis, varying degrees of interstitial fibrosis, focal obliterating bronchiolitis and emphysema.