Idiopathic Fibrotic Nonspecific Interstitial Pneumonia with Cicatricial Organizing Pneumonia and Intraluminal Pulmonary Ossification Containing Bone Marrow

A 72-year-old man presented with bilateral ground-glass opacities in the lower lung fields on chest radiography. Computed chest tomography showed ground-glass opacities and micronodules in both lower lungs. A video-assisted thoracoscopic biopsy of the right lower lung showed homogeneous thickening of the alveolar septa with fibrosis and inflammatory cell infiltration consistent with fibrotic non-specific interstitial pneumonia (fNSIP). Cicatricial organizing pneumonia and intraluminal pulmonary ossification containing bone marrow that was considered to represent dendriform pulmonary ossification. Idiopathic fNSIP was diagnosed. The patient remains stable under antifibrotic treatment.