Radiological features are in keeping with partial superior vena cava obstruction by tumor thrombus extending from metastatic mediastinal lymph nodes from thyroid cancer.  Thyroid cancer can give metastatic nodes at the superior mediastinum along their lymphatic drainage.

Superior vena cava obstruction by invasion with malignancy affecting mediastinum represents ~90% of cases of SVC syndrome, lung cancer, and lymphoma are common causes. Metastatic lymph nodes can also invade SVC forming tumor thrombus.