Thyroid as a Target of Metastases. A Case of Foregut Neuroendocrine Carcinoma with Multiple Abdominal Metastases and a Thyroid Localization after 21 Years

The thyroid gland is quite often the target of metastases. For this reason any thyroid nodule in a patient with a previous history of cancer needs to be evaluated. In case of thyroid metastases, the site of the primary tumor is most often the breast, lung or kidney. A thyroid metastasis from a foregut neuroendocrine tumor is very unusual and requires a differential diagnosis with primary neuroendocrine tumor of the gland itself, i.e., a medullary thyroid carcinoma. This case report is peculiar because of the multiple sites of abdominal relapses, the long time interval between relapses (21 years), and the positive outcome after surgical treatment.