Adult embryonal rhabdomyosarcoma metastatic to the breast and diagnosed by fine needle aspiration - A case report

BACKGROUND: Metastasis to the breast from extramammary malignancies is rare, but its recognition is important. A solitary metastasis must be distinguished from the primary breast cancer because the treatment and prognosis are quite different. CASE: A 30-year-old female presented with a 4.0-cm, solitary, nontender mass in the upper outer quadrant of the right breast 11 months after primary surgery for maxillary sinus embryonal rhabdomyosarcoma. The cytomorphology revealed features of small round cell tumor. Immunocytochemical staining disclosed a positive reaction to vimentin and desmin and negative reaction to cytokeratin, confirming the diagnosis of rhabdomyosarcoma. CONCLUSION: Fine needle aspiration with ancillary studies is essential in the diagnosis of metastatic malignancy of the breast in order to avoid unnecessary mastectomy and to implement appropriate systemic therapy.