A single thyroid nodule revealing early metastases from clear cell renal carcinoma: case report and review of literature

INTRODUCTION: We report the case of an incidental solitary renal cancer cell (RCC) thyroid metastatic nodule treated by thyroidectomy. PRESENTATION OF CASE: A 53 year male presented with a solitary, asymptomatic thyroid nodule. He was treated with left nephrectomy 1 year before for a RCC. Radiological standard follow-up was negative for secondary lesions but ultrasound (US) 12 months after surgery revealed a 1.5 cm solid nodule in the right lobe of the gland. Fine needle aspiration biopsy (FNAB) was inadequate and the patient was submitted to total thyroidectomy. Histology showed the presence of solitary metastasis from RCC. At 2 years follow-up, no evidence of recurrence has been found. DISCUSSION: Solitary RCC metastasis to the thyroid usually occurs late from nephrectomy and have no specific US pattern. When FNAB provides an uncertain cytological results, the patient received thyroidectomy for primary thyroid tumors and diagnosis of metastases from RCC was incidentally made. CONCLUSION: Thyroid nodules in a patient with history of malignancy can pose a diagnostic challenge. The presence of a solitary thyroid nodule in a patient with history of RCC should be carefully suspected for metastasis. We suggest to extend at neck the thorax and abdomen CT scan routinely recommended during the follow-up in high-risk cases. Thyroidectomy may result in prolonged survival in selected cases of isolated thyroid metastasis from RCC.