From "traction bronchiectasis" to honeycombing in idiopathic pulmonary fibrosis: A spectrum of bronchiolar remodeling also in radiology?

Background: The diagnostic and prognostic impact of traction bronchiectasis on high resolution CT scan (HRCT) in patients suspected to have idiopathic pulmonary fibrosis (IPF) is increasing significantly.Main body: Recent data demonstrated that cysts in honeycombing areas are covered by epithelium expressing bronchiolar markers. In IPF bronchiolization is the final consequence of a variety of pathogenic events starting from alveolar stem cell exhaustion, and ending in a abnormal/dysplastic proliferation of bronchiolar epithelium. CT scan features of traction bronchiectasis and honeycombing should be interpreted under the light of these new pathogenetic and morphologic considerations.Short conclusion: We suggest that in IPF subjects traction bronchiectasis and honeycombing -now defined as distinct entities on HRCT scan-are actually diverse aspects of a continuous spectrum of lung remodeling.