From practical point of view, we should add the RAD51B::NUDT3 fusion into the spectrum of fusions which can occur in leiomyocellular tumors, but has never been described in tumors of other histogenesis including inflammatory myofibroblastic tumor, endometrial stromal tumors, and tumors with kinase fusions such as NTRK, RET, and ROS1. Based on this, this fusion seems to be specific for tumors with leiomyocellular differentiation. The gene discussed is ROS1; the disease is endometrial stromal tumor.