<prompt> A female presents with history of progressive breathlessness. Histology shows heterogenous patchy fibrosis with several fibroblastic foci. The most likely diagnosis is:Cryptogenic Organizing PneumoniaNon Specific Interstitial pneumoniaUsual Interstitial PneumoniaDesquamative Interstitial Pneumonia  <response>: Histologic hallmark of UIP is a heterogeneous appearance at low magnification with alternating areas of normal lung, interstitial inflammation, foci of proliferating fibroblasts, dense collagen fibrosis and honeycomb changes. Ref: Harrisons Principles of Internal Medicine, 16th Edition, Page 1557. 