Renal metastases as the initial presentation of papillary thyroid carcinoma: A case report and literature review

Distant metastasis of thyroid carcinoma is rare, and it occurs particularly rarely in renal regions, which represent ~3% of all thyroid distant metastases, with fewer than 30 single case study reports existing in the literature. The present study (and subsequent literature review) of papillary thyroid carcinoma (PTC) reports the case of a 53-year-old male patient who presented with a left renal mass and who had no previous history of thyroid disease. Following renal and thyroid surgery, postoperative pathology confirmed the case to be a follicular variant of PTC, accompanied by renal metastasis. The patient exhibited brain metastasis during a later follow-up. In conclusion, thyroid metastases to the renal site are extremely rare events, particularly for men who present initially with renal neoplasms, which may easily be misdiagnosed as renal cell carcinoma. PTC tends to have a good prognosis; however, when it is accompanied by distant metastasis, the prognosis becomes less favorable.