In situ analysis by SEM-EDX spectroscopy of 10 sarcoidosis cases from MINASARC study

Introduction: MINASARC is a case-control study designed to assess the inorganic “exposome” by a specific questionnaire concomitantly with the mineralogical analysis (MA) of Broncho-Alveolar Lavage (BAL) by transmission electron microscopy (MA-TEM) and paraffin embedded biopsy by scanning electron microscopy (MA-SEM). We report the results obtained by MA-SEM from 10 sarcoidosis cases. Objectives: To compare the results of MA-SEM and MA-TEM. Methods: 5 mediastinal lymph nodes obtained by endobronchial ultrasound trans-bronchial needle aspiration (EBUS/TBNA) and 5 bronchial biopsies (BB) were studied by SEM-EDX. Results: * + to ++++: level of particles load Discussion and conclusion: MA-SEM on tissue sections is feasible and may give potential interesting results. In one manicurist (n°4), it identified silica particles in the lymph node and a high level in BAL. In a fire safety worker (n°10), it identified steel particles associated to a steel overload in the BAL. However, we have to be cautious for interpretation of EBUS/TBNA collected samples, as we identified FeCrNi and TiNi particles compatible with metal particles release from needles used for TBNA, as already reported [Gounant et al., Chest 2010]. MA-SEM on paraffin embedded biopsies allows to determine the chemical composition of particles observed in the preserved structures of tissues. It offers additional information on the patient9s exposure to inorganic dusts.