Clinical impact of the radiological indeterminate for usual interstitial pneumonia pattern on the diagnosis of idiopathic pulmonary fibrosis.

Background: Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease associated with significant morbidity and mortality. The international clinical practice guidelines for the diagnosis of IPF have recently been revised.
Methods: In this single-center retrospective study conducted between June 2006 and March 2018, 27 patients with a newly classified indeterminate for usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) who had undergone surgical lung biopsy were enrolled at the Japanese Red Cross Medical Center. Clinical and pathological characteristics and prognosis were retrospectively analyzed from patient records.
Results: On the basis of multidisciplinary discussion (MDD), IPF was diagnosed in six patients (22%), unclassifiable interstitial pneumonia in 5 (19%), chronic hypersensitivity pneumonitis in 10 (37%), collagen vascular disease-associated interstitial lung disease in 5 (19%), and lymphoproliferative disorder in 1 (4%) patient. Ground-glass opacity, peribronchovascular distribution, upper or middle lobe distribution, mosaic attenuation, consolidation patterns, and honeycombing were found on HRCT. Histological UIP or probable UIP was observed in seven patients. The median survival time from the initial visit was 2770 days (92.3 months). There was a significant difference in survival time in the GAP stage and honeycombing on HRCT according to the log-rank test.
Conclusions: Patients with an indeterminate for UIP pattern on HRCT were more likely to have non-IPF than IPF through pathological diagnosis and MDD. GAP stage and honeycombing on HRCT may be significant risk factors for all-cause mortality.
Competing Interests: Conflict of interest The authors declare that they have no competing interests.
(Copyright © 2020 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.)