Usual Interstitial Pneumonia - Diagnosis

Diagnosis

UIP may be diagnosed by a radiologist using a computed tomogram of the chest (CT scan of the chest), or by a pathologist using tissue obtained by a lung biopsy. Radiologically, the main feature required for a confident diagnosis of UIP is honeycomb change in the periphery and the lower portions (bases) of the lungs. The histologic hallmarks of UIP, as seen in lung tissue under a microscope by a pathologist, are interstitial fibrosis in a "patchwork pattern", honeycomb change and fibroblast foci (see images below).

• Pathological findings in usual interstitial pneumonia (UIP)

• Appearance of usual interstitial pneumonia (UIP) in a surgical lung biopsy at low magnification. The tissue is stained with hematoxylin (purple dye) and eosin (pink dye) to make it visible. The pink areas in this picture represent lung fibrosis (collagen stains pink). Note the "patchwork" (quilt-like) pattern of the fibrosis.

• Appearance of honeycomb change in a surgical lung biopsy at low magnification. The dilated spaces seen here are filled with mucin. Hematoxylin-eosin stain, low magnification.

• A fibroblast focus in a surgical lung biopsy of UIP. Hematoxylin-eosin stain, high magnification. The white space to the left is an airspace. The pale area to the right is a fibroblast focus. It is an area of active fibroblast proliferation within the interstitium of the lung.