Uterine metastases from extragenital cancer are rarely reported in the literature. More frequently, the female genital tract is involved by direct extension from an adjacent pelvic organ. A 37-year-old woman had a myoma of the uterine wall and hypermenorrhea. The mass was laparoscopically enucleated, and frozen section examination was performed because it was macroscopically suspicious for sarcomatoid degeneration. The final diagnosis was metastatic carcinoma in the uterus of probable breast origin.