8409 Thyroid Nodules A to V: A Discussion on Thyroid Nodules and a Case Report of a Rare Thyroid Arteriovenous Malformation

Abstract

Abstract Disclosure: M. Townsend: None. M. Brennan: None. C. Kazmierczak: None. P. Czako: None. Introduction: Thyroid nodules are an increasingly common finding on imaging, and the differential is broad. Arteriovenous malformations (AVMs) are a very rare cause of thyroid lesions, with only 6 reported cases to date. Given their scarcity, there is a lack of information regarding these lesions and how they are diagnosed and managed. Our case aims to address these gaps in information. Case: A 58-yo female with a history of hypertension was found by her PCP to have an enlarged left thyroid lobe with a new left sided bruit and palpable thrill. She had undergone prior thyroid ultrasonography for the enlarged left thyroid lobe which noted dilated and tortuous vascular structures at the posterior aspect of the left thyroid consistent with varices. These were being monitored clinically. Thyroid function tests were all normal. Due to concern for atherosclerotic disease, carotid ultrasound was obtained and showed patent carotid arteries with a large left sided thyroid mass. CTA of the neck revealed the mass to be a large (6.0 x 3.0 x 2.4 cm) AVM centered at the left thyroid gland. She underwent diagnostic angiography that confirmed the size of the mass and showed predominant arterial supply from the left superior thyroidal artery as well as bilateral inferior thyroidal arteries. Since the patient was asymptomatic with no reported neck pain, dysphagia or dyspnea, non-operative management with angioembolization was pursued given the risk of significant blood loss with surgical intervention. Following angioembolization, the results and adequacy of treatment are to be followed with repeat imaging given the high risk of reoccurrence. Discussion: AVMs of the thyroid are a very rare but clinically significant cause of thyroid lesions. Left untreated, they can grow in size and lead to compression of the esophagus or trachea, serious bleeding and high output heart failure. Their presentation is often non-specific and on routine thyroid imaging they can be difficult to differentiate from malignant tumors or varices, as in the case of our patient. Management prioritizes embolization, either alone or in conjunction with surgery, depending on the clinical scenario. Regardless of the treatment modality, reoccurrence rates remain high. Conclusion: Our case aims to add to the available information about thyroid AVMs and discuss the clinical presentation, challenges in diagnosis, imaging findings and treatment modalities available to manage these lesions. Presentation: 6/2/2024