Background: Despite the apparent low incidence of cancer metastatic to the thyroid, autopsy and clinical series suggest it is more common than generally. Although lung, renal, and breast cancer are probably the most common primary sites, a number of cancers have been reported to metastasize to the thyroid synchronously with diagnosis of primary tumor or years after apparently curative treatment.
Case presentation: We report a rare case of a hepatocellular carcinoma metasatic to the thyroid. The patient presented seven months after original diagnosis and treatment with hepatic lobectomy with multiple neck lesions producing a mass effect on the trachea and bilateral lymphadenopathy. Fine-needle aspiration revealed highly anaplastic carcinoma, and immunohistochemistry confirmed hepatocellular carcinoma. The patient received total thyroidectomy as palliative therapy because of the presence of multiple recurrent lesions in the liver.
Conclusion: Clinicians should consider the possibility of metastatic cancer in each patient who presents with a new thyroid mass, especially those with a history of cancer, however remote. In cases where cytology or histology is not diagnostic, immunohistochemistry may be definitive in making the diagnosis.