Yet, EWSR1 break-apart occurs in several morphological mimics of EwS such as DSRCT harboring a pathognomonic EWSR1-WT1 fusion, and angiomatoid fibrous histiocytoma (AFH) commonly positive for EWSR1-ATF1 fusions (Figure 1). The gene discussed is ATF1; the disease is desmoplastic small round cell tumor.