Table 1.

Main tomographic and histopathological findings in hypersensitivity pneumonitis.

	Acute	Insidious manifestations
		Subacute	Chronic
Tomographic findings	Ground-glass opacities and consolidations	Centrilobular ground-glass micronodules; sparse/diffuse ground-glass opacities; air trapping, usually lobular; cysts	Reticular opacities, in some cases peribronchovascular; honeycombing; ground-glass opacities; centrilobular micronodules and air trapping; predominance in the middle lung fields
Histopathological findings	Diffuse alveolar damage; inflammation; signs of vasculitis	Cellular bronchiolitis and chronic peribronchovascular lymphocytic and plasma cell inflammatory infiltrates; non-caseous granulomas, giant cells with cholesterol clefts; Schaumann bodies and foamy macrophages	Fibrosis with a pattern that resembles usual interstitial pneumonia or nonspecific interstitial pneumonia and a peribronchovascular distribution; Schaumann bodies, giant cells, and granulomas; architectural distortion