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.