Stage III includes: IIIA: T3a, N0, M0; IIIB: T3b, N0, M0; IIIC: T1-3, N1, M0. T1: Uterine corpus endometrial stroma sarcoma with tumor limited to the uterus. T2: Uterine corpus endometrial stroma sarcoma with tumor extending beyond the uterus, within the pelvis. T3: Uterine corpus endometrial stroma sarcoma with tumor infiltrating abdominal tissues. T3a: Uterine corpus endometrial stroma sarcoma with tumor infiltrating abdominal tissues at one site. T3b: Uterine corpus endometrial stroma sarcoma with tumor infiltrating abdominal tissues at more than one site. N0: No regional lymph node metastasis. N1: Regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th Ed.) [from NCI]