RESUMEN
BACKGROUND: Usual interstitial pneumonia can present with a probable pattern on high-resolution computed tomography (HRCT), but the probability of identifying usual interstitial pneumonia by surgical lung biopsy in such cases remains controversial. We aimed to determine the final clinical diagnosis in patients with a probable usual interstitial pneumonia pattern on HRCT who were subjected to surgical lung biopsy. METHODS: HRCT images were assessed and categorized by three radiologists, and tissue slides were evaluated by two pathologists, all of whom were blinded to the clinical findings. The final clinical diagnosis was accomplished via a multidisciplinary discussion. Patients with a single layer of honeycombing located outside of the lower lobes on HRCT were not excluded. RESULTS: A total of 50 patients were evaluated. The most common final clinical diagnosis was fibrotic hypersensitivity pneumonitis (38.0%) followed by idiopathic pulmonary fibrosis (24.0%), interstitial lung disease ascribed to gastroesophageal reflux disease (12.0%) and familial interstitial lung disease (10.0%). In the group without environmental exposure (n = 22), 10 patients had a final clinical diagnosis of idiopathic pulmonary fibrosis (45.5%). Irrespective of the final clinical diagnosis, by multivariate Cox analysis, patients with honeycombing, dyspnoea and fibroblastic foci on surgical lung biopsy had a high risk of death. CONCLUSIONS: The most common disease associated with a probable usual interstitial pneumonia pattern on HRCT is fibrotic hypersensitivity pneumonitis followed by idiopathic pulmonary fibrosis and interstitial lung disease ascribed to gastroesophageal reflux disease. In patients without environmental exposure, the frequencies of usual interstitial pneumonia and a final clinical diagnosis of idiopathic pulmonary fibrosis are not sufficiently high to obviate the indications for surgical lung biopsy.