A female in her 70s was referred to the endocrine surgery unit with a 22 mm right thyroid nodule that was incidentally identified on CT. Cytology from an ultrasound-guided fine needle aspirate revealed papillary thyroid carcinoma. After discussion of surgical options, the patient opted to undergo a total thyroidectomy. Intraoperatively, a tumour thrombus was seen encroaching into the middle thyroid vein. The patient made a good recovery postoperatively and was referred for radioactive iodine therapy. Subsequent investigation with F-18 fluorodeoxyglucose ( 18F -FDG) positron emission tomography (PET) scan showed multiple small pulmonary nodules with moderate FDG avidity which were concerning for low volume pulmonary metastasis. Papillary thyroid carcinoma tends to spread lymphatically, and haematogenous spread via direct vascular invasion is rare. The presence of tumour thrombi is associated with higher rates of recurrence and pulmonary metastasis. Tumour thrombi can be asymptomatic, thus imaging plays an important role in preoperative detection. Currently, there is no standardised treatment approach for tumour thrombi in metastatic thyroid cancer.
Kneebone et al. (Sun,) studied this question.