Breast Metastasis from Rhabdomyosarcoma of the Anus in an Adolescent Female

Rhabdomyosarcoma (RMS) of the breast is rare and there is scant information about the clinical behavior and treatment strategies. We report an adolescent female patient with metastatic RMS of the breast from the anus. An 18-year-old female patient was referred to our clinic due to palpable mass in the left breast. At age seven, she was diagnosed with acute lymphoblastic leukemia and treated with chemoradiation therapy. After 10 years of complete remission state, she presented with anal mass which was diagnosed as RMS and she received chemoradiation therapy. After 1 year of complete remission state, she noticed a palpable mass in her left breast. The breast mass was diagnosed as metastatic RMS based on core needle biopsy specimen. The RMS in breast was excised for the decreasing tumor burden despite of another metastatic lesion. Although rarely reported, metastasis of RMS should be considered as a cause of breast mass. Tissue biopsy is recommended when clinically suspected lesion is detected.