Diffuse pulmonary ossification: an unusual interstitial lung disease

Diffuse pulmonary ossification is a rare disease characterized by diffuse small bone fragments in the lung tissue. It can be idiopathic or associated with underlying chronic pulmonary or heart diseases. The majority of cases had been diagnosed on autopsy. This review collects present knowledge of diffuse pulmonary ossification with the purpose of understanding and considering the entity in the differential diagnosis of interstitial lung diseases better.

Diffuse pulmonary ossification is the result of multiple factors that interact enhancing each other. Tissue injury is the most important provoking factor that, in an alkaline environment, initiates precipitation of calcium salts, enables alkaline phosphatase activity, and activates profibrogenic cytokines. Alveolar bleeding is responsible for interstitial metallic deposition that attracts calcium salts and multinucleated giant cells. High-resolution computed tomography scan in the mediastinal window facilitates the detection of bone density lesions and provides diagnosis by using low-invasive method. Reports on the efficacy of bisphosphonates and warfarin in the management of heterotopic ossification encourage further investigation.

Diffuse pulmonary ossification is still underrecognized during life. Its relevance concerning the increasing age of population and longer survival of patients with chronic diseases is underrated. A timely diagnosis will enable a better understanding of pathogenesis and natural course of disease thus paving the way to new therapeutic strategies.