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A6458 - Endobronchial Ultrasound Guided Transbronchial Needle Aspiration in Histoplasmosis Diagnosis
Author Block: T. Vandemoortele, G. Courteau Godmaire; Pulmonology, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
Introduction: Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) is a widely recognized and accepted intervention for diagnosis and staging of lung cancer. The diagnostic yield of this technique has also been demonstrated in granulomatous diseases, particularly sarcoidosis. Data concerning the diagnostic role and utility of EBUS-TBNA in pulmonary fungal infections, such as histoplasmosis, is sparse. We report a case of chronic pulmonary histoplasmosis diagnosed with EBUS-TBNA in an immunocompetent patient living in a moderately endemic region of North America.
Clinical case: The patient, a 52 years old man, known for a past history of lachrymal sac neoplasia and a Hodgkin lymphoma over 20 years ago presented with a chief complaint of increased rhinorrhea and retropharyngeal secretions. He was otherwise doing well with no pulmonary or constitutional symptoms. As part of the initial investigation, a chest radiography revealed possible pulmonary nodules. The chest computed tomography showed multiple bilateral pulmonary nodules and micronodules highly suspicious of a metastatic disease. A cavitary nodule in the right inferior lobe also pointed toward a metastatic disease from a squamous cell carcinoma. The positron emission tomography scan showed a 15 mm subcarinal lymph node with a significant metabolic activity (SUVmax: 4.3). In this context, the patient underwent an EBUS-TBNA to initially rule out a malignant disease. Lymph node biopsy showed no malignant process, no acid-fast bacilli, extensive necrotic areas and fungal elements on Grocott staining compatible with histoplasmosis. Histoplasma urine and plasma antigen were negative.
Discussion: The high diagnostic yield of EBUS TBNA in malignant and some non-malignant conditions has been well demonstrated in the literature. Current recommendations for Histoplasma diagnosis suggest selecting different methods to increase the diagnostic yield – serology, antigen detection, sputum cultures, biopsy samples – depending on the clinical presentation. Even with these methods, subacute and chronic histoplasmosis remain difficult to identify. Previous reports have demonstrated a diagnostic rate up to 78% with EBUS-TBNA for histoplasmosis from highly endemic regions. This case adds to the limited but growing evidence that EBUS-TBNA could be used to effectively diagnose fungal disease in a minimally invasive procedure. It also suggests that it could have a value in discriminating between different mediastinal adenopathy etiologies in patients where a fungal disease is not the most highly suspected diagnosis in regions with a moderate Histoplasma burden. This has not been demonstrated in large studies yet.