[A case of chronic bird fancier's lung in which VATS biopsy was diagnostically useful].

A 72-year-old woman was admitted to our hospital complaining of dry cough and dyspnea on effort for 9 months. Her chest HRCT findings showed diffuse reticular opacities, ground-glass opacities, and interlobular septal thickening with subpleural and peribronchovascular distribution, not typical of IPF/UIP. BAL revealed mild lymphocytosis and elevated CD4/CD8 ratio. Since TBLB was not diagnostic, we performed VATS biopsy. The pathological finding by VATS biopsy revealed collapse, fibrosis, and scar formation in both subpleural and intralobular regions with small granuloma, consistent with chronic hypersensitivity pneumonitis. Both antibodies in serum to pigeon dropping extract and inhalation provocation test using avian dropping extracts were positive. and therefore we diagnosed chronic bird fancier's lung. We should suspect chronic hypersensitivity pneumonitis in cases with HRCT findings atypical of IPF/UIP. and examine antibodies against specific antigens and perform VATS biopsy.