Clinical implications of granulomatous inflammation detected by endobronchial ultrasound transbronchial needle aspiration in patients with suspected cancer recurrence in the mediastinum

BACKGROUND Granulomatous inflammation has been previously reported in association with cancer. Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) is a new minimally invasive test for investigating mediastinal lymphadenopathy. The identification of granulomatous inflammation by EBUS-TBNA and the clinical implications of such detection in a series of patients with previously treated cancer and new mediastinal lymphadenopathy has not previously been performed. METHODS All 153 consecutive patients undergoing EBUS-TBNA in an academic cancer institution for suspected cancer in the mediastinum (mediastinal lymphadenopathy by CT imaging) were reviewed. Patients with non-caseating granuloma identified by EBUS-TBNA were included. RESULTS EBUS-TBNA identified non-caseating granuloma in 17/153 (11%) patients. A subset of 8/153 (5.2%) had sarcoid like lymphadenopathy mimicking cancer recurrence (5/5 PET positive). Another 8/153 (5.2%) patients with new mediastinal lymphadenopathy and no prior history of cancer had a clinical syndrome consistent with sarcoidosis. One other patient with a history of breast cancer was diagnosed with non-tuberculous mycobacteria infection. No patient required mediastinoscopy and there were no complications. CONCLUSION In an academic cancer institute, at least 5% of patients undergoing EBUS-TBNA have sarcoid-like lymphadenopathy mimicking cancer recurrence. Further studies to define the precise etiology, natural history and prognosis of this phenomenon are warranted.