Thyroid metastasis from colorectal cancer: role of [18F]-fluoro-2-deoxy-D-glucose positron emission tomography.

We present a patient with colon carcinoma metastatic to the thyroid. Review of the literature reveals only a few reports of metastatic colorectal carcinoma to the thyroid. Metastatic tumors of the thyroid are no longer considered rare. Unfortunately, they often remain undetected because only a small minority of patients present with a mass lesion or enlargement of the gland. This is further evidenced by the fact that most reports come from autopsy series. Establishing this diagnosis is important because metastatic deposits in the thyroid can sometimes cause respiratory compromise as well as thyrotoxicosis.