IDIOPATHIC DIFFUSE PULMONARY OSSIFICATION: A RARE CAUSE OF CALCIFIED PULMONARY NODULES

Abstract

SESSION TITLE: Medical Student/Resident Diffuse Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Idiopathic diffuse pulmonary ossification is an extremely rare disease that often presents incidentally on chest imaging. While the initial course can often be indolent, the disease course can be severe, and in some cases, fatal. Here, we describe a case of a 21-year-old female who was incidentally diagnosed with diffuse pulmonary ossification. CASE PRESENTATION: The patient underwent tuberculin skin test for school clearance and was noted to have induration to 16 mm with subsequent negative QuantiFERON gold testing. Chest radiograph showed diffuse bilateral peribronchial thickening and nodular interstitial abnormality. The patient reported mild progressive dyspnea on exertion and intermittent dry cough. Her vital signs were unremarkable including an oxygen saturation of 97% on room air. On exam, her lungs were clear to auscultation. Initial computed tomography (CT) scan of the chest showed extensive bilateral centrilobular and peribronchvascular nodules with varying levels of calcification (image 1). Repeat CT scan at 3 months showed no change. Laboratory investigations including calcium, phosphate, sputum acid-fast bacilli, fungal serologies, and rheumatologic screen were normal. Spirometry showed an isolated mild reduction in the DLCO. Bronchoscopy with transbronchial cryobiopsy of the RLL showed pulmonary parenchyma with focal ossification without granulomas, malignancy or amyloid. Cultures were negative. DISCUSSION: Diffuse pulmonary ossification involves the formation of mature bone in the lung and occurs in two forms: nodular and dendriform, both of which can have idiopathic and secondary forms [1, 2]. Ossification typically presents in older men, though has been reported in women or younger adults. Commonly, patients present with absent to minimal symptoms of dyspnea and radiographic findings are out of proportion to symptoms. Spirometry testing is often initially normal but can develop a restrictive pattern with decreased DCLO in later stages. Chest imaging findings include bilateral diffuse calcified micronodules or dense ground glass opacities, with predilection for the lower lobes. Pathology typically reveals ossification and calcification within the alveoli. In later stages, alveolar septal thickening and interstitial fibrosis may develop. Diagnosis can often be made on imaging findings alone, though it can be confirmed with bronchoscopic or surgical biopsy if diagnosis is uncertain. Therapies target lowering serum calcium levels, though no treatments have been shown to affect the progression of disease. For patients with a more aggressive course, lung transplant may be considered [3]. CONCLUSIONS: Pulmonary ossification is a rare, often asymptomatic disorder, that should be suspected in patients with characteristic imaging findings. Early identification can help to monitor progression, though no clear disease modifying therapies have been identified. Reference #1: 1.Tseung J, Duflou J. Diffuse pulmonary ossification: an uncommon incidental autopsy finding. Pathology 38: 45-48, 2006. Reference #2: 2. Reddy TL, von der Thüsen J, Walsh SL. Idiopathic dendriform pulmonary ossification. J Thorac Imaging 27: W108-W110, 2012. Reference #3: 3. Matsuo H. et al, Progressive Restrictive Ventilatory Impairment in Idiopathic Diffuse Pulmonary Ossification Intern Med. 2018 Jun 1; 57(11): 1631–1636 DISCLOSURES: No relevant relationships by Jessica Channick, source=Web Response My spouse/partner as a Consultant relationship with Actelion Please note: $20001 - $100000 Added 04/20/2020 by Colleen Channick, source=Web Response, value=Consulting fee My spouse/partner as a Consultant relationship with Bayer Please note: $5001 - $20000 Added 04/20/2020 by Colleen Channick, source=Web Response, value=Consulting fee No relevant relationships by Tamas Dolinay, source=Web Response