Abstract YO5
Case summary
Breast cancer metastases to the thyroid gland are rare with less than 0.2% documented by fine needle aspiration biopsy (FNAB) and aided by immunohistochemistry (IHC).
We present a case of a 65-year-old female diagnosed case of breast cancer who presented with enlarging anterior neck mass with associated dysphagia. FDG PET/CT scan was done revealing hypodense mass with intense FDG uptake involving the right thyroid, isthmus and a portion of the left lobe with bilateral neck lymphadenopathies.
Patient was referred to head and neck surgery where fine-needle aspiration biopsy was done revealing atypical cells suspicious for malignancy. Total Thyroidectomy with Modified Radical Neck Dissection was done with findings of grossly enlarged thyroid gland with multiple solid masses on bilateral lobes and multiple cervical lymph nodes on levels I-IV with encasement of right carotid artery, right vagus nerve, recurrent laryngeal nerve and 1st tracheal ring on the right. Histopathology of the thyroid gland revealed poorly differentiated carcinoma, diffusely including all lobes with extrathyroidal extension and muscle invasion, perineural and lymphovascular space invasion present. Immunohistochemistry suggested findings of metastatic carcinoma of breast origin. Breast biomarkers revealed ER-negative, PR-negative, Her2/neu negative.
Multidisciplinary Tumor Conference was held and patient was referred to Radiation Oncology delivering 50Gy in 25 fractions to the bilateral neck with boost up to 66Gy in 33 fractions to the supraclavicular fossa with suspicious node.
On repeat Neck CT scan, there was no CT evidence of enhancing mass or fluid collection in the surgicalbeds.
On continued surveillance after 2 years with PET/CT scan, there was no recurrence elsewhere.
In conclusion, many case reports suggested that metastasis to the thyroid gland may confer poor prognosis. Locoregional treatment in the form of thyroidectomy and radiotherapy can provide tumor control and may result in prolonged disease-free survival.