Biopsy in idiopathic pulmonary fibrosis: back to the future.

Idiopathic Pulmonary Fibrosis (IPF) is a relentlessly progressive, fibrosing interstitial pneumonia characterized by a radiologic and/or histologic pattern of usual interstitial pneumonia (UIP). The availability of two effective anti-fibrotic drugs in IPF has encouraged the identification and treatment of patients in early stages in order to maximize clinical benefit. The ability of high-resolution computed tomography (HRCT) to identify a 'definite' UIP pattern is suboptimal, particularly in the absence of honeycombing. Therefore, radiologic criteria for UIP are currently being redefined. Histology represents the major source of information to define a UIP pattern. Novel and less invasive approaches (particularly cryobiopsy) to sample interstitial lung diseases have demonstrated high sensitivity and specificity. In parallel, researchers are focusing on molecular mechanisms underlying IPF with the aim to identify more specific druggable targets. Lung tissue is therefore essential for diagnostic, pathogenetic and therapeutic purposes. Areas covered: We identified and critically reviewed the most relevant recent literature related to the limitations of current radiologic criteria, new lung sampling procedures, and molecular pathways in support of the need of lung tissue to better understand IPF. Expert commentary: The development of truly effective treatments for IPF requires the identification of key pathogenetic molecules and pathways. To this end, the availability of lung tissue is vital.