Concomitant contribution of endobronchial ultrasound cytology and pet-CT investigation in mediastinal lymph node associated with non-sarcoidosis interstitial lung diseases.

INTRODUCTION: Intra-thoracic lymph nodes (ILNs) are often visible on CT scans of patients with interstitial lung diseases (ILDs). Potential reasons for this include non-specific inflammatory processes, exposure to dust, infection, and neoplasia. In some cases, invasive or minimally invasive diagnostic procedures are necessary to categorise them. The aim of this study was to report on the prevalence of different cytological diagnoses obtained by endobronchial ultrasound (EBUS) from ILNs associated with ILD and to describe ILN morphological features on CT scans and 18-fluorodeoxyglucose PET-CT scans. The study also aimed to determine predictive factors for these investigations in assessing the underlying diagnosis. METHODS: For this study, 31 patients who underwent EBUS for ILNs associated with ILD (sarcoidosis excluded) were included retrospectively. The patients had an average age of 63.8 years and 21 of them were male. Eighteen of the patients were smokers or former smokers. RESULTS: ILN cytology was normal in 20 cases (64.5%), showed anthracosis deposits in eight cases (25.8%), and revealed malignant cells in three cases (9.6%). There was no correlation between cytological diagnoses and CT features. Patients with cancer had higher mean SUV_(max) (p = 0.040) and SUV_(max) of the most hypermetabolic ILN (p = 0.034) on PET-CT scans. Bivariate analysis revealed that patients with malignancy had hypermetabolic ILNs that were restricted to a smaller number of ILNs (p = 0.002), had larger short-axis sizes (p = 0.031) and had less homogeneous ILN structures (p = 0.043). CONCLUSION: Although ILNs in patients with ILDs appear to be primarily associated with the inflammatory process of ILD or anthracosis, few imaging features can predict malignancy. This highlights the importance of EBUS in this context.