Comparison of the yield of 19-G eXcelon core needle to a 21-G EBUS needle during endobronchial ultrasound guided transbronchial needle aspiration of mediastinal lymph nodes for the detection of granulomas in cases of suspected sarcoidosis

Granulomatous diseases are thought to be the most common cause of mediastinal adenopathy (1). Endobronchial ultrasound aided bronchoscopic transbronchial needle aspiration (EBUS-TBNA) provides us with a mechanism to perform lymph node biopsies under real time ultrasound guidance (1). However, the diagnostic performance of EBUS-TBNA using the traditional 21-G needle is obfuscated to some extent because of the lack of its ability to supply core biopsy from lymph nodes and hence failing to demonstrate granulomas in a significant number of cases (15%) (2). The diagnosis of sarcoidosis requires the clear demonstration of a non-caseating granuloma (3). Some authors have used the presence of epithelioid cells alone from EBUS-TBNA samples for diagnosing sarcoidosis which has resulted in >90% sensitivity for the procedure using the 21-G EBUS needle but further analysis based on presence of granulomas have reduced their yields to <70% (4). The 19-G core needle used for conventional TBNA (c-TBNA) can provide a histological core (5). Although achieving histological cores with a 22-G needle has been previously reported (in 92% cases), the relevance of such “core biopsies” is unclear (6). Cores were reported to be available in 92% of 22-G EBUS-TBNA samples. However, this report goes on to document that histological material leading to diagnosis was available in only 57% of the cases (6). It leads us to question whether such histological cores obtained by the 22-G needle are of the same diagnostic utility as a true core biopsy. Thus, one well-recognized drawback of EBUS-TBNA has been lack of preserved cellular architecture on needle aspirates using the 22-G and 21-G needles. Few studies have addressed the questions whether a 21-G EBUS-TBNA needle has a higher diagnostic yield compared to a 22-G needle. Unfortunately, the verdict is far from being clear (7). Hence, we have used the 19-G conventional TBNA needle to perform a hybrid EBUS TBNA for those patients with an initial negative 21-G EBUS-TBNA biopsy yet have a high possibility of having sarcoidosis. We aim to review our single center experience with the 19-G core needle biopsy used with an EBUS bronchoscope in this paper. This is a hybrid procedure that used a 19-G c-TBNA needle fitted to a regular EBUS bronchoscope in order to provide core samples under direct visualization. The procedure is described in the online supplement. We then systemically evaluated whether performing EBUS with a 19-G core needle resulted in an increased yield of granulomas than regular EBUS TBNA with a 21-G needle alone. A specific 19-G