Diffuse pulmonary ossification in permanent vegetative state.

Diffuse pulmonary ossification (DPO) is a rare condition characterized by diffuse metaplastic bone formation in the lungs. Two patterns have been described: dendriform, with a coral-like network of bone spiculae along the alveolar septa; and nodular, with lobulated fragments in the alveolar spaces. Dendriform DPO is frequently associated with chronic pulmonary pathologies. We present here the first case of DPO associated with a long-lasting vegetative state. Micro-computed tomography (MicroCT) was applied to analyze the distribution of pulmonary ossification in volumes of lung samples. It showed a mean volume percentage of ossification of 0.79% and 3-D reconstructions permitted to reveal the branching pattern and internal cavities of some ossifications. The occurrence of DPO in a persistent vegetative state (PVS) may be favored by recurrent pulmonary infections, due to aspiration and immunological defects, and respiratory instability, due to brain damage and the fact of being bedridden. Fibrotic reactions probably represent a preliminary step in bone formation. Further studies could examine the incidence and clinical significance of DPO in subjects in PVS or patients who are bedridden for other reasons. MicroCT may facilitate analysis of more case histories, with greater sensitivity with respect to classic microscopic analyses.