Horner's Syndrome During High-Intensity Focused Ultrasound Ablation for a Benign Thyroid Nodule

Abstract

Objective: Horner's syndrome (HS) is a rare complication of high-intensity focused ultrasound (HIFU) and radiofrequency ablation for thyroid nodules. We present such a case and discuss how to avoid this complication in the future.

Methods: This case occurred during HIFU treatment of a benign thyroid nodule (BTN). Ultrasound and fine-needle aspiration cytology (FNAC) were performed before the procedure. Volume reduction was evaluated at 6 weeks, 3, 6, and 12 months. Technical success was ≥50% reduction at 6 months.

Results: A 30-year-old woman presented with a solitary symptomatic thyroid nodule. Her thyroid stimulating hormone was 1.16 (ref 0.4-3.6) μUI/mL), ultrasound found a 13 mL right-thyroid EU-TIRADS 4 nodule. Two FNACs were read as Bethesda II. The subsequent HIFU procedure was conducted with local 2% lidocaine anesthesia. The procedure was painful (visual analogic scale 10/10) and ipsilateral partial ptosis occurred during the procedure. Volume reduction at 12 months was 34.6% of the initial volume with persisting functional and cosmetic complaints, discomfort, and partial ptosis. As the volume reduction was ≤50%, the procedure was a technical failure. A new FNAC was read as Bethesda IV. A right lobectomy was performed without postoperative outcomes and without requiring hormonal replacement therapy. Pathological evaluation found no malignant cells.

Conclusion: HS is a rare complication of HIFU for management of BTNs. It may be symptomatic and have sequalae that persist for months. Severe neck pain may by associated, but further investigation is needed.

Keywords: BTN, benign thyroid nodule; CSC, cervical sympathetic chain; EU-TIRADS, European thyroid image reporting and data system; HIFU, high-intensity focused ultrasound; HS, Horner’s syndrome; Horner’s syndrome; LA, laser ablation; RFA, radiofrequency ablation; TA, thermal ablation; TN, thyroid nodule; TSH, thyroid stimulating hormone; US, ultrasound; VRR, Volume reduction rate; benign thyroid nodule; high-intensity focused ultrasound (HIFU); image-guided ablation.

Fig. 1

A right-lobe thyroid nodule treated by high-intensity focused ultrasound (HIFU). The nodule is solid, EU-TIRADS 4, and has combined intranodular and perinodular vascularization. The carotid artery, sympathetic nervous system, and recurrent laryngeal nerve “danger zone” is indicated. CA = carotid artery; CSC = sympathetic nervous system; RN = recurrent laryngeal nerve.

Fig. 2

High-intensity focused ultrasound (HIFU) preprocedure assessment. The nodule is automatically divided (Beamotion version TUS 3.2.2, Theraclion) into multiple ablation voxels. Each voxel received a continuous 8-s pulse of HIFU energy (blue and white). Structures like the ipsilateral carotid artery, trachea, recurrent laryngeal nerve zone, and skin safety margins (arrows) were marked out on the treatment screen before the start of the procedure.

Fig. 3

Right (ipsilateral) Horner syndrome clinical description and follow-up at 2 hours, 24 hours, 6 weeks, and 6 months). Images of the patient’s eyes at each follow-up visit are shown.