Histologically Proven Dendriform Pulmonary Ossification: A Five-case Series.

Dendriform pulmonary ossification (DPO) is a rare condition characterized by metaplastic bone formation in the lung parenchyma. It has been reported to be often associated with primary lung diseases, such as usual interstitial pneumonia (UIP) or chronic aspiration of gastric acid; however, its clinical features and pathophysiology remain unclear, especially in idiopathic cases. We herein report five DPO cases, including three with an idiopathic origin. In all cases of idiopathic DPO, the pathological and radiological examinations showed localized pulmonary lesions suggesting inflammation or hemorrhaging.