ESR1 and tumor of uterus: Second, GREB1-rearranged uterine tumours frequently lacked overt sex cord morphology: while all 7 ESR1::NCOA2/3 UTROSCTs demonstrated corded, nested, trabecular and/or tubular/sertoliform patterns, only 1 GREB1-rearranged uterine tumour displayed a prominent trabecular pattern, with the remaining cases showing exclusively or predominantly diffuse/solid growth.<h4>Conclusions</h4>Overall, our findings confirm that GREB1-rearranged uterine tumours are part of the UTROSCT spectrum, though they frequently exhibit a more diffuse growth pattern and a higher degree of genomic instability.