Fine needle aspiration (FNA) cytology of the thyroid is a test in which cells are aspirated from thyroid tumors by puncture under ultrasound guidance and the tumors are diagnosed as benign or malignant based on the shape and properties of the cells. It is a simple test and is routinely performed on an outpatient basis, but in rare cases serious complications may occur. Some patients develop transient diffuse thyroid swelling after fine needle aspiration (dTSaFNA) cytology of the thyroid, and present with symptoms of anterior neck swelling, neck pain, neck pressure, and dyspnea. We encountered one such case that required hospitalization. The patient was a 29-year-old man with no significant past medical history. He was referred to our department because of a thyroid tumor that happened to be incidentally detected by MRI. He had no palpable mass in the anterior neck. Ultrasound examination showed a well-circumscribed tumor measuring 22 × 14 × 13 mm in size in the upper pole of the right lobe of the thyroid. Ultrasound-guided FNA cytology was performed. After the puncture, there was no swelling in the neck and the patient was sent home. However, bilateral anterior neck swelling and tenderness were observed, and ultrasound examination and computed tomography (CT) revealed diffuse swelling and crack-like gaps in both lobes of the thyroid, as well as edema in the anterior neck muscles. There was no laryngeal edema. The patient was admitted and started on hydrocortisone sodium succinate 300 mg to reduce the edema. By 15 hours after the puncture, the swelling of the anterior neck had improved markedly, and no laryngeal edema was observed, and the patient was discharged. By the 8th day after the thyroid puncture, the anterior neck swelling had completely resolved. The cytology result was Class II.
In patients developing dTSaFNA after FNA, the possibility of occurrence of airway emergencies must also be borne in mind and careful follow-up is necessary. Patients should be fully informed of the possible risks prior to undergoing FNA.
