[A male with ossification of the lungs].

A 71-year old man, known with unclassified pulmonary fibrosis for years, shows dendriform pulmonary ossification (DPO) on a chest CT-scan after spontaneous pneumothorax. DPO is a rare finding with a mostly benign, slowly progressive course. Pneumothorax is an uncommon but clinically important complication of DPO with high chance of recurrence.