Middle thyroid vein tumour thrombus in papillary thyroid carcinoma

Area of Science:

• Endocrinology
• Oncology
• Radiology

Background:

• Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer.
• While PTC typically spreads via lymphatic pathways, direct vascular invasion and hematogenous spread are rare but concerning.
• Tumor thrombi in the thyroid vasculature represent direct vascular invasion and are associated with increased recurrence and metastasis risk.

Purpose of the Study:

• To report a case of incidentally discovered papillary thyroid carcinoma with intraoperative identification of a tumor thrombus.
• To discuss the implications of tumor thrombi in metastatic thyroid cancer.
• To emphasize the role of imaging in the preoperative detection of tumor thrombi.

Main Methods:

• A 70s female patient with an incidentally found thyroid nodule underwent fine needle aspiration (FNA) biopsy.
• Diagnosis of papillary thyroid carcinoma was confirmed by cytology.
• Total thyroidectomy was performed, during which a tumor thrombus in the middle thyroid vein was observed.
• Postoperative F-18 fluorodeoxyglucose (^18F-FDG) positron emission tomography (PET) scan was utilized for staging.

Main Results:

• Papillary thyroid carcinoma was diagnosed via FNA.
• Intraoperative visualization confirmed a tumor thrombus encroaching into the middle thyroid vein.
• ^18F-FDG PET scan revealed multiple small pulmonary nodules with moderate FDG avidity, suggestive of low-volume pulmonary metastasis.

Conclusions:

• The presence of tumor thrombi in papillary thyroid carcinoma, though rare, is linked to a higher risk of recurrence and metastasis.
• Asymptomatic tumor thrombi underscore the critical role of preoperative imaging for detection.
• There is currently no standardized treatment protocol for managing tumor thrombi in metastatic thyroid cancer.