Diffuse Pulmonary Ossification:
View cases of pulmonary ossificans
Clinical:
Diffuse pulmonary ossification (DPO) is a process in which metaplastic ectopic bone is present in lung tissue- the result of actual bone deposition by osteoblasts (pulmonary fibroblasts can differentiate into osteoblasts in response to local hypoxia or acidosis) [3]. It most commonly affects the lower lobes. DPO is usually discovered in association with some other underlying pulmonary disease such as interstitial fibrosis (can be seen in up to 28.5% of patients- and can appear dendriform [2]), recurrent bronchopneumonia, amyloidosis, chronic aspiration, or pulmonary edema (particularly with mitral stenosis).The condition may be:
1) Dendriform- tree-like, with characteristic branching along terminal airways that may be interpreted as fibrosis on plain film radiograph.
2) Nodular- which tends to be more circumscribed and situated in the alveolar spaces and appears as mutliple, small (less than 1 cm) subpleural calcifications which can mimic old granulomatous disease. Nodular pulmonary ossification tends to occur in the setting of chronically elevated pulmonary venous pressures, particularly due to chronic mitral stenosis or left heart failure [3]. It represents pathologic ossification in areas of chronic airspace hemosiderosis and organizing pneumonia and appears as small high attenuation centrilobular nodules that may coalesce [3].
On histologic analysis, the abnormality is composed of mature lamellar bone.
REFERENCES:
(1) Chest 1992; 102 (5): 1614-1615
(2) Radiology 2017; Egashira R, et al. Diffuse pulmonary
ossification in fibrosing interstitial lung diseases: prevalence
and associations. 284: 255-263
(3) AJR 2017; Gruden JF, et al. Dendriform pulmonary ossification
in the absence of usual interstitial pneumonia: CT features and
possible association with recurrent aspiration. 209: 1209-1215
