Metastasis of Renal Cell Carcinoma to the Parathyroid Gland 12 Years After Radical Nephrectomy

Renal cell carcinoma (RCC) accounts for 2-3% of all malignant tumors in adults. RCC is well-known for its propensity to metastasize to unusual sites, and late metastasis, even after several years, is common. Involvement of the parathyroid gland has only four reported cases in literature. A 62-year-old Caucasian man was referred to our department due to an enlarging cervical mass. The patient's relevant past medical history included a left nephrectomy for RCC 12 years ago. After right thyroid lobectomy and isthmectomy, histopathology revealed an intrathyroidal nodule corresponding to the parathyroid gland with metastatic RCC. Approximately one-third of RCC subjects with apparently localized disease will develop metastasis, even several years after nephrectomy. The literature is sparse regarding the most appropriate follow-up approach for these patients. We describe a rare case of nodular goiter of the thyroid gland concurrent with metastatic RCC to an intrathyroidal parathyroid gland, without disseminated systemic metastasis.