Three Cases of Idiopathic Diffuse Pulmonary Ossification

: Diffuse pulmonary ossification (DPO) is an uncommon diffuse lung disease characterized by metaplastic bone formation in the lung parenchyma and is rarely diagnosed in life. While DPO usually occurs as a secondary disease, idiopathic cases are extremely rare. We describe three cases of idiopathic DPO, two of which were definitively diagnosed by surgical lung biopsy. One case was observed in a 43-year-old man with a history of recurrent pneumothorax who developed pneumothorax after the surgical biopsy. Few reports have described cases of DPO with recurrent pneumothorax; however, pneumothorax should be considered as a potential complication when such patients are encountered.