October 2013, Vol 144, No. 4_MeetingAbstracts Signs and Symptoms of Chest Diseases | October 2013
A Rare Case of Idiopathic Dendriform Pulmonary Ossification Tsuyoshi Takahashi, MD; Makoto Tanaka, MD; Tetsuo Yamaguchi, PhD JR Tokyo General Hospital, Tokyo, Japan Chest. 2013;144(4_MeetingAbstracts):944A. doi:10.1378/chest.1702957
Abstract SESSION TITLE: Miscellaneous Global Case Reports SESSION TYPE: Global Case Report PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM INTRODUCTION: Dendriform pulmonary ossification (DPO) is defined as disseminated, widespread heterotopic bone formation within the lungs. DPO is a rare disease and is usually associated with restrictive pulmonary diseases, such as interstitial pneumonia or fibrosis. Herein, we report an extremely rare case of idiopathic DPO. CASE PRESENTATION: A 50-year-old man was diagnosed with pulmonary sarcoidosis, presenting as bilateral diffuse pulmonary shadows on chest computed tomography (CT), 17 years ago and has been administered prednisolone since then. The patient’s new attending physician noticed that the pulmonary shadows did not show an appearance typical of pulmonary sarcoidosis. Therefore, the patient was referred to our hospital for detailed investigation. The patient had no medical or familial history of interest. Laboratory data were within normal limits. Chest CT revealed linear and reticular opacities with calcification in both lungs. Lung biopsy with video-assisted thoracoscopic surgery showed the most striking intraoperative finding: pearllike hard materials in the pulmonary parenchyema. Histological findings showed dendriform mature bone formations with fatty marrow in the alveolar spaces but no findings of interstitial pneumonia or fibrosis. The patient is being followed up but no medications have been prescribed. DISCUSSION: The exact mechanisms underlying DPO are unclear, but some studies have shown that DPO is associated with restrictive pulmonary diseases such as interstitial pneumonia or fibrosis. On the other hand, idiopathic DPO, as in this case, is an extremely rare. The clinical course of DPO is considered indolent or slowly progressive. DPO has rarely been diagnosed antemortem, but it may be more prevalent than is thought. In this case, the patient was misdiagnosed as having pulmonary sarcoidosis, which resulted in prolonged overtreatment. CONCLUSIONS: This case highlights that the possibility of DPO should be considered in patients with diffuse pulmonary shadows with calcification. Reference #1: Joines RW, Roggi VL. Dendriform pulmonary ossification: Report of two cases with unique findings. Am J Clin Pathol 1989; 91: 398-402
Reference #2: Gielis JF, Luijks M, Negels J et al. Pulmonary ossification seen centrally in a lung tumor. Ann Thorac Surg 2012; 93: 153-4 Reference #3: Freid ED, Godwin TA. Extensive diffuse pulmonary ossification. Chest 1992; 102: 1614-5 DISCLOSURE: The following authors have nothing to disclose: Tsuyoshi Takahashi, Makoto Tanaka, Tetsuo Yamaguchi No Product/Research Disclosure Information