Metastasis of renal cell carcinoma to the thyroid gland 9 years after nephrectomy: A case report and literature review

We report a case presenting with thyroid and lung metastases of renal cell carcinoma that was treated with molecular targeted therapy followed metastasectomy. A 52-year-old female underwent radical nephrectomy of right renal cell carcinoma in 2007. The patient presented 9 years after nephrectomy at the age of 61 years with sudden loss of vision on the left side and a mass on the neck. On magnetic resonance imagining, there was a mass on the midline of the neck, extending to the left, measuring 46 x 31 mm and containing central cystic-necrotic areas. Fine-needle aspiration biopsy was performed. The histopathological examination of the biopsy specimen revealed a lesion composed of malignant epithelial cells compatible with metastasis of renal carcinoma. Computed tomography showed multiple metastases in bilateral lungs. Metastasectomy and total tiroidectomy were performed. Thyroid and lung metastasis of renal cell carcinoma were pathologically confirmed. But on the first computed tomography after metastasectomy, there was residual tumor in the thyroid. Interferon-alpha therapy was given for 8 weeks. After that, pazopanib therapy started. Three months later, on computed tomography, residual metastatic foci were regressed. The patient was followed up for 1 year after metastasectomy. The patient is currently receiving a single dose of pazopanib per day (400 mg/day) and the general condition is good. Thyroid metastasis should be considered in patients with a thyroid nodule and positive history for renal cell carcinoma. Successful results can be obtained with metastasectomy and systemic targeted therapy.