To the Editors:
In the June issue of the European Respiratory Journal, Wong et al. 1 describe the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in a cohort of 65 patients with suspected sarcoidosis. EBUS-TBNA correctly identified noncaseating granuloma in 56 out of 61 patients, who were ultimately diagnosed with sarcoidosis. Thus, the authors’ pre-test criteria for sarcoid were correct in 61 (94%) out of 65 patients. Some readers may therefore argue that EBUS-TBNA was not required if sarcoidosis can be so accurately identified by a combination of clinical and radiographical information. While the authors clearly excluded patients with “suspected or known malignancy”, it is nonetheless surprising that no other causes of mediastinal lymphadenopathy, such as lymphoma, metastatic cancer or infection, were identified in this cohort. In fact, in clinical practice, the reason for performing EBUS-TBNA in patients with diffuse mediastinal lymphadenopathy is to rule out malignancy and infection, as it is often difficult to distinguish stage 1 sarcoidosis from, for instance, lymphoma or granulomatous infection. This important study highlights the diagnostic yield of EBUS-TBNA in an inordinately high-prevalence sarcoidosis population but leaves open the question of general applicability.
A prospective study is warranted, investigating the added benefit of endobronchial ultrasound-guided transbronchial needle aspiration to routine bronchoscopy with transbronchial lung biopsy in a more heterogeneous population of patients with idiopathic mediastinal lymphadenopathy.
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