Endocrine Abstracts

Background: While needle tract seeding has long been recognized as an uncommon complication of the fine needle aspiration (FNA) of the thyroid nodules, seeding tumor metastasis resulted from subcutaneous hematoma following FNA is extremely rare. Herein, we present a challenging case of skin metastasis of papillary thyroid carcinoma as a late complication of subcutaneous hematoma associated with fine needle aspiration.

Clinical case: A 57-year-old male presented with anterior neck mass for 6 months. Neck ultrasound revealed a huge cystic mass with a hypervascularity exophytic solid nodule, 2.7 cm in diameter at the left thyroid lobe. Approximately 55 ml of hemorrhagic fluid was aspirated and followed by FNA of the solid component with a 23-gauge needle. Two days later, he returned with swollen and ecchymosis of the surrounding neck. The cervical hematoma resolved conservatively and total thyroidectomy was done one month later. Classic variant of papillary thyroid carcinoma (PTC) in the left thyroid gland with lymphatic invasion was found. No metastatic lymph node was detected. Postoperative high-dose radioiodine (RAI) ablation and thyroxine suppressive therapy were given. He was doing well with persistent biochemical incomplete response at one year after treatments and subsequently lost to follow-up. He came back two years later with palpable multiple subcutaneous nodules along the right side of the neck for 3 months. Ultrasound revealed small well-defined nodules (0.3 to 0.7 cm in diameter) located superficially over the right sternomastoid muscle. Further investigations revealed no distant metastases. Neck reoperation confirmed skin metastasis of PTC. The patient was in stable condition with persistent biochemical incomplete response at the last follow-up.

Conclusions: FNA of the thyroid is regarded as a safe procedure. However, physicians should be watchful of hemorrhagic complications in high-risk patients and aware that late complications such as seeding tumors could develop many years after bleeding complications.