SAT486 A Case of Superior Vena Cava Syndrome Caused by Untreated Multinodular Goiter

Disclosure: K. Blanchard: None. C. Musurakis: None. A. Ojha: None. C.P. Barsano: None. A. Havrylyan: None. A 92-year-old female with heart failure, COPD, obstructive sleep apnea, longstanding exertional dyspnea, and a 15-year history of a toxic multinodular thyroid on methimazole presented to our emergency department with one week of right arm swelling. Physical exam showed a 4 cm midline goiter with right-sided jugular venous distention and right upper extremity pitting edema. On admission, TSH, free T4 and free T3 levels were within normal limits on methimazole 5 mg daily. PTT, PT and INR were normal. Thyroglobulin antibodies and TSI measured two years prior were normal. Right arm venous duplex was negative for acute deep venous thrombosis (DVT) but showed heterogenous structures in the right neck with collateral vessels, likely related to a large multinodular thyroid gland with substernal extension. Left arm venous duplex showed chronic sequela of DVT in the left central subclavian vein. Chest x-ray revealed right-sided tracheal deviation due to goiter. A CT chest performed 6 months prior revealed a massive multinodular goiter with mass effect on the trachea, narrowing the tracheal opening to only 7 mm (ref 10-21 mm in females) and significant mass effect upon adjacent venous structures with resultant collateralized flow. Of note, the patient has a 15-year documented history of this goiter and repeatedly declined aggressive surgical intervention. We recommended ENT consultation for minimally invasive treatment options. ENT recommended thoracic surgery evaluation at a tertiary center and suggested tracheal stenting as a possible solution. Regarding the chronic left subclavian vein thrombosis, the patient opted to forego anticoagulation therapy after discussion of risk versus benefit. She again declined surgical evaluation and was discharged home with primary care and Endocrinology outpatient follow-up. Superior vena cava (SVC) syndrome is the result of either a partial or complete obstruction of the SVC, resulting in symptoms such as upper extremity swelling, dyspnea, cough, face or neck swelling, and dilated venous collaterals in the chest. Compression of the SVC by a mediastinal malignancy is the most common cause of SVC syndrome. However, retrosternal goiter as a cause is extremely rare, with only a few cases previously reported in the literature. Interestingly, the incidence of malignancy in retrosternal goiters is reported to be as high as 35 percent. Large intrathoracic goiters are primarily seen in long periods of neglected disease, as in our patient. The presence of a substernal goiter, regardless of symptoms, is an indication for thyroidectomy, as this is the only way to prevent mediastinal enlargement of the goiter. Non-surgical treatment options documented in the literature include temporary tracheal stent placement followed by radiofrequency thyroid ablation and ultrasound-guided needle aspiration of a dominant thyroid cyst. Presentation Date: Saturday, June 17, 2023