SESSION TITLE: Interstitial Lung Disease Case Report Posters I
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Silicoprotenosis and pulmonary alveolar proteinosis(PAP) are rare lung disease with histological presentation due to abnormal accumulation of lipoproteinacous material in the lung. Acute silica exposure, temporal relation and radiologic finding of centrilobular nodules and consolidation are key to diagnosis of silicoproteinosis. We present a case with 9 years exposure to silica in coal mining with radiologic and histologic feature of PAP and having silica in the lung.
CASE PRESENTATION: 40-year-old caucasian male presented with rapidly worsening shortness of breath over three months with dry cough and weight loss. He is a coal miner by profession with exposure to dust and coal over 9 years. On examination he was hypoxic with clubbing and crackles. Chest X-ray showed progression of the alveolar and interstitial opacities over last 2 months. Recent chest tomography shows geographic areas of bilateral ground-glass opacities with superimposed interlobular septal thickening suggesting “crazy paving appearance” (Figure 1). BAL return was cloudy pink with no fungus or PJP on GMS stain. Transbronchial biopsy showed deposits of acellular, homogenous eosinophilic material within alveolar spaces. Material was PAS positive confirming PAP. Slides also revealed weakly birefringent particles on polarized light suggestive of silica in lung.
DISCUSSION: Silicoproteinosis is a pathologic variant of acute silicosis due to abnormal accumulation of proteinaceous material similar to PAP. It occurs due to abnormal high exposure of silica dust. The imaging features of silicoproteinosis include centrilobular nodules(both solid and ground glass in attenuation) and consolidative opacities, predominantly dependent on distribution. Foci of calcification within regions of consolidation and lymph odes are also commonly seen. The pathogenesis of alveolar proteinosis though not clear may be related to type II cell hyperplasia and alveolar macrophage dysfunction from silica dust leading to abnormal production of proteinaceous material and inability to clear by dysfunctioned macrophages. Secondary PAP from silica dust has been documented by various case studies with similar pathogeneis. Coal miners are also exposed to silica dust and there is strong association of silicosis in coal miner workers. Our patient radiologically and histologically presented as PAP, but also had silica dust in the lung thus making it hard to label whether he has silicoprotenosis or secondary PAP from silica dust.
CONCLUSIONS: Coal miner worker with radiologic features of PAP, should have suspicion of silica exposure and should be worked up for birefringent material on pathology. Secondary PAP from silica and silicoproteinosis could be spectrum of the same disease having same pathogenesis.
Reference #1: Marchiori E et al. Silicoproteinosis: high-resolution CT findings in 13 patients. AJR Am J Roentgenol. 2007 Dec;189(6):1402-6.
DISCLOSURE: The following authors have nothing to disclose: Debasis Sahoo, Edwin Jackson, Amit Banga, Ruchi Yadav, Carol Farver, Atul Mehta
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