EBUS‐FNA diagnosis of metastatic FUS‐ERG ‐rearranged extraskeletal Ewing sarcoma following 15 years with untreated metastatic recurrence

This case report demonstrates challenges in the cytological diagnosis of metastatic extraskeletal Ewing sarcoma from an endobronchial ultrasound-guided fine needle aspiration biopsy and the important role of ancillary molecular analysis. It also adds to the small number of Ewing sarcoma with FUS-ERG fusion in the literature by highlighting an exceptionally indolent clinical course over 15 years of slowly progressing pulmonary metastases in the absence of any treatment.