Cicatricial Organizing Pneumonia with Dendriform Pulmonary Ossification: An Unusual Cause for a Recurrent Pneumothorax

Table 2

Differential diagnosis of pulmonary calcifications and ossifications.

Calcifications
Dystrophic: calcifications in diseased lung	(1) Infections: granulomatous infection such as histoplasmosis and tuberculosis and viral infections such as varicella
	(2) Granulomatous noninfectious disease: sarcoidosis
	(3) Occupational lung disease: silicosis, coal workers’ pneumoconiosis
	(4) Metabolic lung diseases: amyloidosis, pulmonary alveolar microlithiasis
Metastatic: calcifications in normal lung	(1) Hypercalcemia in the setting of chronic renal failure, other causes of primary hyperparathyroidism, Paget’s disease, parathyroid carcinoma or multiple myeloma
Calcified metastasis	(1) Metastases such as mucinous carcinoma, chondrosarcoma and synovial sarcoma
Ossifications
NPO	In patients with chronic venous congestion such as long standing mitral stenosis
DPO	In patients with interstitial fibrosis
Bone forming neoplasms	Osteogenic sarcoma metastasis

Modified from reference [8]. NPO: nodular pulmonary ossification, DPO: dendriform pulmonary ossification.