ERBB3 and uterine corpus sarcoma: We herein describe the detailed clinicopathological and molecular findings of a novel uterine sarcoma characterized by a neurogenic-like (S100/SOX10-positive) immunophenotype and activating mutations involving members of the epidermal growth factor receptor (EGFR/ERBB) family of tyrosine kinases ERBB3 (HER3) and ERBB2 (HER2) to alert pathologists to this rare but possible underdiagnosed entity with therapeutic implications.