Metastasis from renal cell carcinoma to thyroid presenting as rapidly growing neck mass

Renal cell carcinoma (RCC) is commonly known as the "internist's tumor" because of its unpredictable behavior. Metastasis to the thyroid gland is rarely found in clinical practice.

We report a rare case of non-thyroid malignancies NTM from renal cell carcinoma 1.5 years after radical nephrectomy in a 58-year-old man with a rapidly growing neck mass.

Malignant melanoma, breast carcinoma, lung, and skin cancer are the most common sources of non-thyroid malignancies (NTM). Although metastases of NTMs to the thyroid gland are uncommon in clinical practice, it should be considered in patients with a history of prior malignancy and a new thyroid mass.

Isolated thyroid metastasis should be considered in patients with a previous history of cancer and newly developing thyroid mass.