Role of endobronchial ultrasound in diagnosis and molecular assessment of metastatic melanoma

Background and objective: Vemurafenib is a new inhibitor of the mutated BRAF oncogene. In the presence of mutated BRAF in metastatic melanoma, treatment with vemurafenib leads to a reduction in mortality and in tumour progression when compared with chemotherapy. This study describes nine cases in which endobronchial ultrasound (EBUS) guided transbronchial needle aspiration (TBNA) was used to assess mediastinal and hilar lymph nodes for the presence of metastatic melanoma and demonstrates the ability to detect mutations in BRAF on the tissue obtained.

Methods: A retrospective review was performed of all patients who had a history of melanoma and underwent EBUS TBNA to investigate hilar or mediastinal lymphadenopathy for the presence of metastatic melanoma.

Results: In seven of the nine cases, metastatic melanoma was confirmed on cytology. The two negative cases were proven to be true negatives by follow up or by demonstrating an alternate diagnosis. In five cases, analysis for BRAF mutation was performed. Four cases were positive for mutation and one demonstrated wild-type BRAF.

Conclusions: Tissue samples obtained from EBUS TBNA are adequate to diagnose metastatic melanoma in hilar and mediastinal lymph nodes and to detect the presence or absence of mutations in the BRAF gene. Our findings suggest that close collaboration between bronchoscopists and pathologists will be needed to implement BRAF testing in routine practice in the era of targeted therapy.