Dendriform pulmonary ossification.

Four cases of dendriform pulmonary ossification are reported from postmortem roentgenography of isolated lungs. All showed pathoanatomical evidence of chronic fibrosing, mostly interstitial, rarely intraalveolar pneumonia, besides the typical manifestations of dendriform pulmonary ossification. Microscopy revealed fluid transition from proliferating, interstitially increased connective tissue to fully developed osseous structures. These dendriform structures can be seen in some analogy to the structural pattern of interstitial, bronchovascular as well as septal connective tissue; however, actual topographical correlation between bone structures and blood or lymph vessels could not be safely determined. Our observations suggest that dendriform pulmonary ossification may be interpreted as a rare complication, or special manifestation, of chronic fibrosing interstitial inflammation of the lung.