Honeycombing pattern: A particular form of sarcoidosis-related pulmonary fibrosis

Introduction: Pulmonary fibrosis, as defined as radiographic stage 4, is the major cause of morbidity and mortality in sarcoidosis. Three main patterns of pulmonary fibrosis have been described on HRCT: bronchial distorsion, hilo-peripheral linear opacities, and honeycombing (HC). Aims: To determine whether patients with HC pattern have a particular phenotype of sarcoidosis. Methods: Retrospective and monocenter study, comparing 34 patients with HC pattern (men: 62%, age: 56±14 years) with 34 controls with other HRCT pattern. Controls were matched with patients for the date of the first available workup with stage 4. Results: HC predominated in the upper lobes, but 5 cases (15%) had evidence of basal and peripheral predilection close to that seen in idiopathic pulmonary fibrosis. Patients differed from controls for a higher frequency of environment exposure (39 vs 15%, p=0,045), more altered gas exchanges (PaO2: 77±10 vs 82±11 mmHg, p=0,04 and DLCO: 38±16 vs 60±16%, p Conclusion: The phenotype of patients with HC is original. An exposure to inhaled particles may play a role in the development of this particular fibrosis evolution and explain the local respiratory severity of sarcoidosis while the disease seems less active and severe from a systemic point of view.