Rare presentation of metastatic renal cell carcinoma to thyroid gland: A case report

Abstract Introduction Renal cell carcinoma is known to cause metastasis to unusual sites, but metastasis to the thyroid gland is a rare occurrence, not only that, but 20 years after complete recovery is almost nonexistent. Case presentation We are presenting here a case of 79-year-old female who presented to us for asymptomatic progressive thyroid nodule. She had history of right nephrectomy for renal cell carcinoma 20 years ago. Ultrasound guided fine needle aspiration biopsy (FNAB) of the thyroid was non-diagnostic. Total thyroidectomy of the patient was performed, and histopathological evaluation of the specimen revealed the swelling to be of metastatic in nature secondary to renal cell carcinoma. Discussion Despite thyroid metastasis being rare, FNAB can prove to be useful tool for diagnosis of thyroid tumors and metastases and can be inconclusive in some cases. Therefore, immunohistochemistry can prove beneficial in diagnosis such cases. Conclusion The diagnosis of renal cell carcinoma metastasis is made after immunohistochemical evaluation of the thyroidectomy specimen with thyroidectomy proving to be the modality of treatment for such cases with no further radiation therapy and a yearly follow up plan to screen for other lesions.