Renal cell metastasis to the thyroid gland: An emerging phenomenon.

INTRODUCTION: Suspected thyroid malignancies are usually assumed to be primary in origin. Rarely, in 1-3% of cases, the tumour arises from a secondary source such as a melanoma or breast carcinoma. There is a growing body of research concerning metastatic spread of renal cell carcinoma to the thyroid gland.

PRESENTATION OF CASE: This case report describes the presentation and diagnostic work-up of an 84yr male presenting with a goitre and hoarse voice. Histopathological examination of the excised 95 × 65 × 55 mm tissue mass revealed metastatic clear cell renal cell carcinoma.

DISCUSSION: This disease pattern has become increasingly apparent in recent literature. A literature review of 150 documented cases worldwide showed that the mean interval for this spread to occur is 9 years.

CONCLUSION: There is a need for further investigation into the underlying pathophysiology of this phenomenon and increased awareness from clinicians of its existence.