Abstract
BACKGROUND: Although papillary thyroid microcarcinoma (PTMC) is not considered a threatening tumor, in some cases, it can be aggressive. Metastatic thrombosis of papillary thyroid carcinoma, follicular thyroid carcinoma, Hürthle cell carcinoma, poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma have been reported in the literature, but there have been no reports about PTMC. CASE SUMMARY: A 45-year-old woman presented with a thyroid mass and thrombosis in a middle thyroid vein during a physical examination. She had no symptoms, and the physical examination showed no positive signs. Subsequent ultrasonography-guided fine-needle aspiration biopsy results indicated an atypical lesion of ambiguous significance, with some actively growing cells (TBSRTC III) and the BRAF(V600E) mutation not present. This patient underwent left thyroidectomy, isthmus lobectomy, prophylactic central lymph node dissection and thromboembolectomy. Postoperative pathology showed papillary microcarcinoma of the left thyroid, and the thrombus in the middle thyroid vein was a tumor thrombus. CONCLUSION: Middle thyroid vein tumor thrombus is an extremely rare condition in PTMC, but it does exist. Lobectomy and thromboembolectomy may be an option for patients with thrombi in the middle vein of the thyroid, and we strongly suggest close follow-up of these patients.