What is usual interstitial pneumonia (UIP)?

Updated: Jan 02, 2020
  • Author: Eunhee (Joanne) S Yi, MD; Chief Editor: Philip T Cagle, MD  more...
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Answer

Answer

Usual interstitial pneumonia (UIP) refers to a morphologic entity defined by a combination of (1) patchy interstitial fibrosis with alternating areas of normal lung, (2) temporal heterogeneity of fibrosis characterized by scattered fibroblastic foci in the background of dense acellular collagen, and (3) architectural alteration due to chronic scarring or honeycomb change. [1]

The term UIP is often used interchangeably with idiopathic pulmonary fibrosis (IPF), but other clinical conditions are associated with UIP, although less commonly, including collagen vascular disease, drug toxicity, chronic hypersensitivity pneumonitis, asbestosis, familial IPF, and Hermansky-Pudlak syndrome. [1] Thus, UIP is not entirely synonymous with IPF, and diagnosis of IPF requires an exclusion of possible underlying clinical conditions, as mentioned above.


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