Sporadic medullary thyroid carcinoma with a pedunculated intraluminal internal jugular vein recurrence: A case report and literature review.

Medullary thyroid carcinoma (MTC) is an uncommon usually slowly progressing neuroendocrine tumour that arises from calcitonin (CT) producing parafollicular C cells of the thyroid gland. It accounts for approximately 5% of all thyroid cancers. The majority of MTCs are sporadic (75%) whilst 25% are part of the MEN 2 hereditary syndrome (MEN 2A and MEN 2B and familial MTC). Mutations of the proto-oncogene, RET (Rearranged during Transfection), found on chromosome 10q11, are present in more than 95% of hereditary MTCs and about 25% of sporadic MTCs. MTC metastasizes primarily via lymphatic spread, to central, and lateral nodal neck compartments and the anterior and superior mediastinum. Distant haematogenous spread targets the lungs, liver, bone and brain, and is presumed to be secondary to a lymphatic pathway. There are no previously documented reports of a focal pedunculated metastases located within the jugular vein. We present the first reported case of a metastatic MTC lesion found in the right internal jugular vein in a man with recurrent MTC.