Breast sarcoma is a rare entity that accounts for less than 1% of all breast malignancies; it may spread by direct invasion and/or through the blood. Axillary lymph node involvement is extremely rare and usually associated with advanced-stage disease. In the surgical treatment of this neoplasm, complete axillary lymphadenectomy is important for the local clearance of the clinically involved lymph nodes. We report a case of a 65-year-old woman affected by follicular dendritic cell sarcoma of the left breast. Six months after breast surgery she developed an axillary metastasis from the same disease.