MON-479 Acute Thyroid Edema: A Rare Complication of Thyroid Fine Needle Aspiration

Abstract

Background: Acute thyroid swelling is a rare complication of thyroid fine needle aspiration (FNA). The first documented case was in 1982 and to date there are less than 20 cases currently reported in the literature (1). Case Presentation: A 66-year-old female with a history of non-ischemic cardiomyopathy and heart failure was admitted to hospital to expedite heart transplant evaluation. A neck ultrasound was performed due to voice hoarseness and concern for vocal cord nodules. The ultrasound showed a 1.3 cm hypoechoic nodule in the right thyroid lobe. Given that the nodule had irregular borders and microcalcifications, a thyroid FNA was recommended.The patient’s home warfarin had been held for at least three days prior to the biopsy and her INR on the procedure date was 1.4. Her heparin drip was held four hours prior to the thyroid FNA. Immediately following the procedure, a 3.2 cm hematoma formed inferior to the thyroid gland. The heparin drip was restarted 6 hours post-FNA as per radiology’s recommendation. Cytology of the nodule was benign.The patient recovered well post FNA and improvement in the hematoma was noted on exam. Her hemoglobin was stable and she was restarted on warfarin. On day two post thyroid FNA, she reported significant neck pain, with no corresponding increase in the extra-thyroidal hematoma. No stridor or other concerning features were present on exam. A repeat thyroid ultrasound was performed three days after the FNA. It demonstrated fluid filled ‘cracks’ within the thyroid parenchyma and tripling in the volume of the thyroid gland, concerning for diffuse edema. No heterogeneity or subcapsular thickening was seen to suggest hemorrhage, and the previously demonstrated 3.2 cm extra-thyroidal hematoma was not visualized.She was treated with ibuprofen 800 mg and prednisone 30 mg, and noted an improvement in her neck pain with these measures. A repeat ultrasound done three weeks after initial thyroid FNA showed marked improvement of the diffuse swelling. Conclusion: The phenomenon of diffuse thyroid edema after fine need aspiration has been termed acute thyroid swelling (ATS). Given how frequently thyroid fine needle aspirations are performed, ATS appears to be a very rare complication. The etiology of ATS remains unknown, but the use of blood thinners, such as in our patient, does not appear to be a risk factor (1). The radiological appearance of fluid filled ‘cracks’ within the thyroid parenchyma suggests a more diffuse process, rather than a localized reaction. While NSAIDs or steroids may help with symptoms, patients appear to improve irrespective of whether or not medications are given. This suggests that ATS is a self-limiting condition without long term complications. Reference: (1) Polyzos SA, Anastasilakis AD, Arsos. Acute transient thyroid swelling following needle biopsy: An update. Hormones. 2012;11(2);147-150