IJSR International Journal of Scientific Research 2277 - 8179 Indian Society for Health and Advanced Research ijsr-9-8-26688 Original Research Paper Breast cancer metastasis to the thyroid gland: A rare case report with diagnostic dilemma Rawat Dr. Mrinalini M Borkar Dr. August 2020 9 8 01 02 ABSTRACT

Introduction: Metastasis to thyroid gland is very rare; with breast cancer metastasizing to thyroid is extremely rare. Here, we report a case of metastatic lesion in the thyroid from breast carcinoma in a 43 year old female who presented to us with a right breast lump for 1.5 years along with thyroid swelling for 6 months. Results: FNAC of breast lump showed ductal carcinoma while FNAC of thyroid nodule was inconclusive. CECT showed right breast neoplasm with malignant deposits in isthmus of thyroid. She underwent right simple mastectomy with axillary clearance and total thyroidectomy followed by chemotherapy. Histopathology analysis showed invasive ductal carcinoma in isthmus of thyroid.This was confirmed by immunohistochemistry, which revealed positive for GATA– 3and negative for TTF1 and Calcitonin. Conclusion: This case report highlights the importance of a correct early diagnostic work up.Immunohistochemical panels are helpful in differentiating between primary and secondary tumors.Also, thyroidectomy may be beneficial for local disease control and prevent the potential morbidity of tumor extension related to airway.