Unusual Thyroid Carcinoma Metastases: a Case Series and Literature Review

The most common sites of metastatic differentiated thyroid cancer are the neck lymph nodes, while distant metastases typically involve the lungs, the bones, and less frequently the brain. Uncommon metastatic sites include the liver, adrenal gland, kidney, pancreas, and skin. The epidemiological aspects of thyroid metastases in rare sites are largely unknown and their identification could have a significant impact on patients management. A mini-series of unusual metastatic sites of thyroid carcinoma is proposed as a contribution to current knowledge on anatomopathological characteristics and clinical outcome. Of the six cases that were assessed, the metastases were the following: skin metastases (2), skin and pancreas metastases (1), renal metastasis (1), adrenal metastasis (1), and liver metastasis (1). In our experience, metastases in rare sites do not always represent a negative prognostic factor for disease outcome. In fact they can occur as single distant lesion and if surgically resectable, their treatment can also lead to local disease remission.