Etiology of benign mediastinal/hilar lymphadenopathy

BACKGROUND AND OBJECTİVE: Mediastinal/hilar lymphadenopathy includes a group of diseases with a broad spectrum of etiologies. The most common causes are lymphoma, metastatic carcinoma, sarcoidosis and tuberculosis. The differential diagnosis of diseases causing benign mediastinal/hilar lymphadenopathy has been challenging. Data associated with clinical, histopathological and radiological properties of patients diagnosed as having benign mediastinal/hilar LAP and their prognosis was evaluated in this study. We aimed to have the findings of this study to be guiding in the differential diagnosis and follow-up of benign mediastinal/hilar lymphadenopathy. METHODS: Our study was conducted at Karadeniz Technical University, Department of Chest Diseases prospectively between May 2015 and June 2016. Cases that underwent EBUS/ Mediastinoscopy / Thoracoscopy with the diagnosis of mediastinal/hilar lymphadenopathy were included in the study and patients who were diagnosed to have malignancy in the initial biopsy were excluded from the study. Patients' demographics, clinical informations (smoking and tuberculosis history, drugs, comorbidity), laboratory parameters (sedimentation, calcium, ACE, ARB), pulmonary function tests, radiological findings (thorax CT, PET), invasive procedures (EBUS, mediastinoscopy, thoracoscopy) and pathology results were reviewed. After the initial sampling of the lymph node, "first diagnosis" was made according to clinical / radiological / laboratory / histopathologic results. "Final diagnosis" was made after follow-up and second-time lymph node sampling of some patients. RESULTS: The included 93 cases consisted of 40.9% men (38) and 59.1% women (55) with a median age of 55.1 (±12.6) years. Patients underwent EBUS TBNA (83 patients), mediastinoscopy (7 patients), thoracoscopy (2 patients) and thoracotomy (1 patient). A second diagnostic procedure was performed in 19 patients whose initial biopsy result was benign. When evaluated by the results of the second biopsy, 52.7 % (49), 32.3% (30), 9.7% (9), 4.3% (4), 1.1% (1) of the patients were found to have granulomatous lymphadenitis, anthracosis, reactive hyperplasia, unclassified and malignancy, respectively. In conclusion, the final diagnosis of the patients was accepted to be sarcoidosis in 50 (53.8%), anthracosis in 12 (12.9%), tuberculosis in 5 (5.1%), silicosis in 4 (4.3%), churg strauss syndrome in 1 (1.1%), hypersensitivity pneumonia in 1 (1.1%), infectious in 1 (1.1%), malignancy in 1 (1.1%) and uncertain in 18 (19.4%). A minimum of 3 months clinical–radiological follow-up was successfully achieved in 47 patients; stable in 39 (83%) patients, regression in 7 (14.9%), progression in 1 (2.1%). The mean follow-up duration was 6.4±3.1 months. CONCLUSIONS: It has been found that mediastinal/hilar LAP's can be sampled by EBUS TBNA method to a large extent and that the diagnosis can be performed by mediastinoscopy when the first approach is inadequate. Also it has been found that benign pathologies played an important part in the etiology of mediastinal/hilar LAP's; benign mediastinal/hilar LAP's were generally presented in the form of granulomas; sarcoidosis was the primary cause among the cases of granulomatous lymphadenitis and silicosis and TB could also be seen, although rarely. In cases with impossible differential diagnosis, follow-up of clinical, radiological and pulmonary functions may direct one to diagnosis in time.