Fine-needle aspiration biopsy of the thyroid is essential to accurately diagnose thyroid tumors. We report a case in which diffuse thyroid swelling developed immediately after fine-needle aspiration biopsy of the thyroid in a 42-year-old man who underwent ultrasound-guided fine-needle aspiration biopsy for a left-sided thyroid tumor. The patient developed neck pressure and swelling immediately after the biopsy, with diffuse swelling across the right side of his neck. Immediate thyroid ultrasonography and computed tomography revealed swelling, cracking, and vasodilatation throughout the right lobe of the thyroid. Visual inspection performed 4 hours after the puncture showed reduction of the neck swelling, and physical examination and imaging studies revealed subsidence of the swelling the following day.
Neck swelling after puncture is commonly attributable to hematoma formation and transient thyroid enlargement in response to puncture stimulation. While the precise mechanism underlying the development of diffuse thyroid swelling remains unclear, we speculate that puncture stimulation releases vasodilators that increase the vascular permeability and blood flow to the area, resulting in rapid diffuse thyroid swelling.
It is necessary to closely monitor patients in the hospital for approximately 30 min after the puncture before they are discharged. Ultrasonography and careful follow-up are warranted to distinguish between hematoma and transient thyroid enlargement in patients with post-puncture neck swelling, for prompt administration of appropriate treatment.
