Metastatic rhabdomyosarcoma to the breast

Secondary malignancy metastatic to the breast is uncommon, with an incidence of 0.5% to 3% of patients with extramammary malignancy. Although rhabdomyosarcoma is a common aggressive primary malignancy in the pediatric age group, metastatic deposits to the breast rarely occur and are mainly seen in adolescent girls. Here, we report an intriguing, rare adult case with metastasis to the breast from nasal rhabdomyosarcoma. A 31-year-old woman with the complaint of right neck mass noted recently came to this hospital for help. She had a history of nasal malignancy treated with radiotherapy in another hospital three months previously. Physical examination revealed multiple neck masses at bilateral neck areas. Bilateral neck dissection was performed and rhabdomyosarcoma, metastatic to lymph node, was the final diagnosis. One year after operation, the patient felt a large lump in her left breast. Surgical excision was performed and histological analysis was consistent with rhabdomyoblastic origin. Secondary malignancy metastatic to the breast is uncommon, yet this entity does exist. In view of the therapeutic implication, a metastatic breast lesion should not be mistaken as the primary breast carcinoma. Only with the awareness of such a possibility can prompt diagnosis and optimal treatment be achieved.