Airway-centered Interstitial Fibrosis Involving Smooth Muscle Hyperplasia with Severe Pulmonary Hypertension.

In the 2013 updated classification of the American Thoracic Society/European Respiratory Society, airway-centered interstitial fibrosis (ACIF) is included as a bronchiolocentric pattern of interstitial pneumonia (IP) among idiopathic IPs. We encountered a case of severe pulmonary hypertension (PH) with chronic IP. The patient initially presented with shortness of breath and often lost consciousness due to PH, and seven years after his first visit, he ultimately died. An autopsy revealed ACIF and usual IP. In particular, the ACIF comprised non-atypical smooth muscle hyperplasia, and pulmonary hypertensive vascular degeneration was detected. This case may represent a new pathological feature of ACIF.