Particle Analysis by Scanning Electron Microscopy With Energy Dispersive X-Ray Analysis in Pulmonary Pathology Specimens From US Military Service Members Deployed During the Global War on Terror 2002 to 2015

Introduction: Between 2001 and 2015, 2.77 million U.S. military service members completed over 5 million deployments to Southwest Asia. There are concerns that deployment-related environmental exposures may be associated with adverse pulmonary health outcomes. Accurate pulmonary diagnosis often requires histopathological biopsy. These lung biopsies are amenable to chemical analysis of retained particulates using scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDXA). Method: A retrospective review of SEM/EDXA data collected in conjunction with pathologic diagnostic consultations at the Joint Pathology Center from 2011 to 2016 was conducted. Sections adjacent to those obtained for pathologic diagnosis were prepared for SEM/EDXA particle analysis, which provides qualitative identification of elements present in each particle and semiquantitative estimations of elemental weight percent. The review includes comparison of the particle analysis data and diagnostic findings, the particle count for the standard field analyzed, and types of particles identified. Results: Nonneoplastic lung biopsy specimens from 25 deployed and 7 nondeployed U.S. service members were analyzed as part of the Joint Pathology Center pathologic consultations. The major exogenous particle types identified in both groups include aluminum silicates, other silicates, silica, and titanium dioxide. Endogenous particle types identified include calcium salts and iron-containing particles consistent with hemosiderin. These particles are present in deployed and nondeployed service members and are particle types commonly identified in lung biopsy specimens from urban dwelling adults. Rare particles containing other elements such as cerium and iron alloys were identified in some cases. Possible sources of these materials include diesel fuel and occupational and other environmental exposures. Conclusion: Scanning electron microscopy with energy dispersive X-ray particle analysis of inhaled particulates retained in lung tissue from deployed service members identifies particles commonly present in inhaled dust. In this small case series, we were not able to detect particle profiles that were common and unique to deployed patients only.