Thyroid Arteriovenous Malformation in Hereditary Hemorrhagic Telangiectasia: Insights on Successful Noninvasive Imaging

<jats:title>Abstract</jats:title> <jats:p>Hereditary hemorrhagic telangiectasia (HHT) causes arteriovenous malformations (AVMs) in several organs. This report is the first to document and image a thyroid AVM complication in HHT.</jats:p> <jats:p>A 72-year-old woman with HHT was referred for thyroid nodule evaluation. Ultrasonography showed a hypervascularized nodule in the right thyroid lobe which was initially suspected to be malignant. However, 3-dimensional computed tomography angiography demonstrated a thyroid AVM with abnormal anastomosis of the superior thyroid artery and the inferior thyroid vein.</jats:p> <jats:p>In the formation of thyroid AVM, here, chronic thyroiditis and hypothyroidism complications may have been a second hit, due to the predisposing first-hit germline mutation.</jats:p> <jats:p>This report sheds light on overlooked thyroid lesions in HHT and advocates a noninvasive imaging approach in diagnosing thyroid AVMs. Furthermore, this case suggests a potential mechanism of AVM formation in human HHT, possibly supporting the second-hit hypothesis.</jats:p>