Pulmonary Mineralizations

OVERVIEW
Both calcification and ossification and may be generalized or localized
Discrete—if individual mineral deposits can be identified
Diffuse—preclude identification of individual deposits
Calcification—dystrophic or metastatic; dystrophic: occurs secondary to tissue degeneration or inflammation; metastatic: occurs secondary to metabolic disease; may be normal (e.g., the pleura in old dogs or premature calcification of the tracheal and bronchial cartilages in chondrodystrophic breeds); often a sign of inactivity of a lesion, thus most focal calcifications are functionally unimportant
Ossification—also called heterotopic bone formation; calcification of a bony matrix; pulmonary ossification in the form of small, multiple nodules (osteomas) common in normal dogs
Generalized pulmonary mineralizations of unknown cause—reported in dogs and cats under descriptive terms: pulmonary alveolar microlithiasis or pumice stone lung, bronchiolar microlithiasis, idiopathic pulmonary calcification or ossification