Bilateral Metastatic Rhabdomyosarcoma to the Breast in an Adolescent Female: Touch Imprint Cytology and Implication of MyoD1 Nuclear Antigen

Background: Rhabdomyosarcoma accounts for approximately 4% of all childhood malignancies. Breast metastases from rhabdomyosarcoma are uncommon with an incidence of 6%. Case Report: We present a patient who developed bilateral mammary metastases from rhabdomyosarcoma arising in the right lower extremity. An 11-year-old female with a 20-month history of rhabdomyosarcoma was referred to our department because of bilateral breast enlargement. A needle core biopsy was performed and touch imprint slides were obtained. Cytology determined the masses to be metastases of rhabdomyosarcoma. MyoD1 immunostain and RT-PCR analysis confirmed the diagnosis. Conclusions: Cytomorphology with ancillary methods is essential in the diagnosis of metastatic breast deposits in order to avoid unnecessary mastectomy and to employ systemic treatment.