-To review the semiologic findings of UIP (usual interstitial pneumonia), the associated radiological pattern of idiopathic pulmonary fibrosis (IPF). -To brievely discuss the pathological findings of UIP. -To illustrate the different diagnostic categories of UIP. -To discuss the differential diagnosis of UIP integrating clinical data and radiological findings. -To highlight the importance of multidisciplinary approach in the setting of a UIP.

Idiopathic Pulmonary Fibrosis is a chronic, progressive, fibrotic interstitial lung disease of unknown cause. If mainly affects older adults, with male predominance, and higher incidence North America and Europe (3 to 9 cases per 100,000 person-years) than in South America and East Asia (fewer than 4 cases per 100,000 person-years). IPF is associated with the histopathologic or radiologic pattern of UIP. Several environmental exposures that target the lung epithelium increase the risk of IPF, with the most consistent evidence being for cigarette smoking. An increased...

· Pathology UIP, the radiologic and also pathologic pattern of IPF, is caractherized by scattered fibroblastic foci with heterogeneous distribution that alternate interstitial inflammation and honeycombing. These findings coexist with normal lung areas. · Imaging findings: Chest x-ray: Imaging findings on a chest X-ray are not specific, even though reticular pattern and bronchiectasis, with lower lobes and costophrenic angles predominance are generally recognised.Fig. 1 MSCT (multi-slice CT): High-quality CT images are essential. Chest CT requires thin sections (<2 mm) and high spatial resolution reconstruction. Images...

IPF is a chronic interstitial disease with fatal outcome. It is essential to make an accurate diagnosis and exclude other potential illnessess that can mimic this condition, since their management and prognosis will be completely different.

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