Follicular thyroid carcinoma with tumour thrombus extending into superior vena cava and right atrium - A case report.

Intra-cardiac extension of tumour thrombus of follicular carcinoma of thyroid is uncommon. We report a case of advanced thyroid carcinoma where tumour thrombus was well profiled with CT scan and transesophageal echo images and extension was noted from SVC into right atrium, with clinical features of superior vena cava syndrome. The clinical significance of the "ring sign" is discussed.