| Background
Follicular thyroid carcinoma represents a significant subset of differentiated thyroid malignancies, ranking as the second most common type after papillary thyroid carcinoma. Unlike papillary carcinoma, follicular carcinoma exhibits a higher propensity for vascular invasion, facilitating hematogenous dissemination and distant metastasis. While microvascular infiltration is recognized, involvement of the internal jugular vein or other major neck vessels is infrequent.
Case Presentation
A 56-year-old female presented with incidentally discovered thyroid nodules during routine health screening. Clinical evaluation revealed palpable enlargement of the right thyroid lobe with ultrasound findings suggestive of right thyroid carcinoma and cervical lymph node metastases. Additionally, tumor thrombus formation was observed within the right internal jugular vein. Fine-needle aspiration pathology confirmed right follicular thyroid carcinoma and cervical lymph node metastases. Surgical management comprised total thyroidectomy, bilateral neck dissection, and right internal jugular vein ligation, followed by adjuvant radioactive iodine therapy. The patient experienced uneventful postoperative recovery.
Discussion
Tumor thrombosis, more prevalent in malignancies with proclivity for microvascular invasion, is frequently encountered in follicular thyroid carcinoma. Its predilection for invading the internal jugular vein or other major neck vessels underscores the potential for superior vena cava syndrome and hematogenous dissemination. Thrombus patterns, delineated into intravascular extension and direct infiltration, correlate closely with prognosis. While thyroid and neck vascular ultrasound offer diagnostic utility, intraoperative findings often guide management. Contrast-enhanced neck imaging aids in diagnosis and surgical planning. Presence of internal jugular vein tumor thrombus portends adverse clinical outcomes, necessitating comprehensive surgical resection and consideration of vascular reconstruction. In addition to TSH suppression therapy after surgery, whether to undergo radioactive iodine 131 (RAI) treatment depends on the presence of residual tumor lesions and distant metastasis. This patient underwent RAI 2 months after surgery due to lung metastasis.
Conclusion
The occurrence of jugular vein thrombosis in follicular thyroid carcinoma is a very rare and serious complication. Preoperative ultrasound examination is advisable for the diagnosis of this disease, but often misdiagnosis or missed diagnosis occurs. Comprehensive neck CT/MRI is necessary, and some patients rely on intraoperative diagnosis. Surgical experts point out that if the internal jugular vein is found to be affected by thyroid cancer and the tumor thrombus is removed, it is recommended to repair or reconstruct the internal jugular vein. After surgery, in addition to TSH inhibition therapy, RAI treatment is an important supplement for patients with distant metastasis or tumor residual. |
