Fine-needle aspiration cytology of renal clear cell carcinoma metastatic to the thyroid gland

摘要

Dear Editor, Although highly vascular, the thyroid is an unusual site for metastatic disease, indeed only approximately 2% of thyroid malignancies are from metastases. Common primary sites in most cases are lung, breast, skin (melanoma), colon, and kidney. Conventional or renal clear cell carcinoma (RCC) comprises 75% of renal carcinomas and is the most common type of tumor to metastasize to the thyroid gland. We report on a 61-year-old woman who previously underwent a right thoraco-abdominal nephrectomy and adrenalectomy for a conventional clear cell RCC, Fuhrman grade n, with a predominant alveolar pattern, composed of mainly clear cells. The tumor had directly invaded the adrenal gland and was staged pT3a (TNM 6th edition). She remained well post surgery until a routine follow-up examination 4 years later showed an enlarged left thyroid gland. She denied any dysphagia, voice change, or neck swelling.