Introduction Radiofrequency ablation (RFA) is a promising, non-surgical method, used for the treatment of benign and malignant thyroid nodules (TN). While this minimally invasive technique has been studied extensively in Europe and Asia, it has been recently adopted in Latin America. The aim of our study is to describe the clinical outcomes following the first cohort of TN subjected to ablative radiofrequency in Ecuador. Methods This single-center, prospective study, carried out at ITECC (Instituto de la Tiroides y Enfermedades de Cabeza y Cuello) in Ecuador, included adults who underwent RFA for benign and malignant thyroid nodules (TN), between September 2020 and January 2022. The trans-isthmic approach and moving shot technique using the RF Medical equipment with an 18G needle and 5 or 7 mm tip were applied. Nodule size and volume, thyroid function, and complications were evaluated before and after RFA. Initial volume and change in TN volume were calculated with the ATA calculator and the independent-samples T-test. Results A total of 26 patients with 28 TNs were included. 25 TNs were benign (Bethesda II) and 3 were micropapillary thyroid cancer (MPTC) (Bethesda VI). In the benign lesions group, most were female (82.6%), <55 years of age (73.9%), euthyroid (62.5%), and symptomatic (95.6%); had a mean maximum diameter of 3.3 ± 1.3 (range: 0.8–5.5) cm and a mean initial volume of 13.1 ± 11.6 ml; and had predominantly solid component (36.4%). A substantial volume reduction was observed since the first month after RFA (1 month: mean volume 8.6 ± 4.2 ml, p=0.01; 6 months: mean volume 4.5 ± 3.9 ml, p=0.04; and 12 months: mean volume 4.9 ± 6.9 ml, p=0.25; vs. baseline). All patients were asymptomatic at the last follow-up. In the MPTC group, two patients were males (66.7%); all were <55 years of age (100.0%) and euthyroid (100.0%); most were asymptomatic diagnosed by routine US (66.7%); had a mean maximum diameter of 0.6 ± 0.1 (range: 0.5–0.8) cm and a mean initial volume of 0.056 ± 0.001 ml. At 1-month follow-up after RFA all TN were fibrosed and no lymph node or distant metastases were found. Finally, in both groups, no major complications were found and only one patient reported ecchymosis at the puncture site. Thyroid function was not affected. Conclusions To the best of our knowledge, we are the pioneers in Ecuador and the third country, after Brazil and Colombia, in Latin America that implemented RFA in the management of TN. In our first experience, RFA was a safe and effective technique. RFA induced a substantial volume reduction, improved symptoms, avoided cosmetic concerns, and did not affect normal thyroid function. Our results are consistent with other series. Data on a longer follow-up are needed to confirm long-term efficacy. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Saturday, June 11, 2022 1:30 p.m. - 1:35 p.m.

Introduction Tracheal invasion is a poor prognostic factor in patients with aggressive thyroid cancer. Crico-tracheal resection and primary anastomosis (CTRA) is the preferred surgical technique. Appropriate resection can improve early postoperative outcomes and long-term oncological outcomes. A recent systematic review of eastern literature showed a moderate rate of postoperative complications. However, there is a paucity of data regarding early postoperative complications in Latin America. Therefore, the aim of this report is to describe the early postoperative outcomes of three patients with thyroid cancer invading the trachea who underwent CTRA in two tertiary referral centers (1 public and 1 private) in a low-income country. Clinical Cases There were 2 females (F1: 53 y, F2: 55 y) and 1 male (M1: 53 y) patients from Ecuador. Patient F1 had follicular variant of papillary thyroid cancer (PTC) and was operated on in the public center and patients F2 and M1 had classic variant of PTC. Neck CT and perioperative flexible endoscopy were performed for airway invasion assessment. All patients underwent total thyroidectomy with circumferential CTRA. Patient F1 had a right lobe thyroid tumor with intraluminal invasion of the 5th tracheal ring up to the cricoid cartilage, the recurrent laryngeal nerve (RLN) and common carotid artery, and bilateral central neck lymph node metastasis. She underwent bilateral central neck dissection, carotid shaving, and RLN resection. Patient F2 showed an enlarged, multinodular thyroid invading the 4th up to the 1st tracheal ring, without luminal compromise. There was no invasion to other structures. Patient M1 had a right lobe thyroid tumor, with intraluminal invasion of the 4th tracheal ring up to the cricoid cartilage and invasion of the RLN. He underwent RLN resection. Patient F1 and M1 were classified as Shin IV and patient F2, Shin III. Regarding the 30-day postoperative complications, patient F1 had tracheostomy infection on day 5, tracheal dehiscence and anastomotic dehiscence that caused massive bleeding, cardiorespiratory failure and death on day 8. Patient M1 only presented mild bleeding through the traqueostomy tube on day 1, non-compressive cervical hematoma on day 2, and was discharged on day 5. Patient F2 had no complications and was discharged on day 3. The last 2 patients were decanulated successfully at the 2-week follow-up and received adjuvant radioactive iodine. Conclusions CTRA seems to be a safe procedure with moderate postoperative complications, low mortality, and zero tracheotomy-dependency rates in patients operated in Ecuador. Our results are similar to those described in the international literature. Further studies are needed to confirm these results and draw robust conclusions. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Introduction Ultrasound-guided Percutaneous Ethanol Ablation (UPEA) is one of the first-line treatments for benign pure cysts and predominantly cystic thyroid nodules (TN). This non-surgical procedure has been used for years worldwide, however, in Latin America, this was recently adopted. Therefore, the aim of this report is to characterize our initial experience with UPEA in Ecuador. Clinical cases description: We report on the cases of a woman (F1: 49 y) and two men (M1: 38 y, M2: 69 y) that underwent UPEA for three predominantly cystic TN at ITECC (Instituto de la Tiroides y Enfermedades de Cabeza y Cuello) in Ecuador. All nodules were non-functioning and graded as Bethesda II. Our approach in regards to the total ethanol volume injected was approximately calculated at 1/3 of the TN volume, using 75% ethanol. 10 ml of 2% lidocaine was used for anesthetic purposes. Initial volume and change in TN volume were calculated with the ATA calculator. Patient F1 had a 40 mm (23.5 ml) right lobe TN and underwent needle extraction of 5 ml of cystic fluid before the injection of 6 ml of ethanol. At 1-month follow-up, the nodule reduced 78.1% in volume (28 mm, 5.1 ml). Similarly, patient M1 had a 59 mm (44.8 ml) right lobe TN treated with 6 ml of ethanol after 20 ml of cystic fluid was extracted from the TN. At 3-month follow-up, the nodule reduced 99% in volume (7 mm, 0.1 ml). Finally, patient M2 had a 36 mm (14.5 ml) right lobe TN treated with 5 ml of ethanol. At 6-moth follow-up, the nodule reduced 99% in volume (0.5 mm, 0.04 ml). No patients developed complications and only needed one session. Conclusions To the best of our knowledge, we are the pioneers in Ecuador and the fourth country in Latin America that implemented UPEA in the management of cystic TN. In this small report, UPEA seems to be an effective and safe treatment option for cystic TN. Patients had >75% reduction in cyst volume along with symptomatic relief and no complications. Our results are consistent with other series. Data on a longer follow-up are needed to confirm long-term efficacy. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

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Background Black thyroid is a rare condition with fewer than 70 cases reported around the globe. Black thyroid is seen almost exclusively in patients upon minocycline ingestion, and the process has previously been thought to be generally benign. Despite the favorable impact of this drug on thyroid function, several studies have reported an association between black thyroid and thyroid cancer. Herein, we report a black thyroid associated with papillary thyroid cancer. Clinical Case A 30-year-old woman with no significant medical history and no risk factors for thyroid cancer, but with a history of acne treated with minocycline for 2 months 10 years ago, came to the office for a thyroid nodule found during a routine healthcare visit. The patient was asymptomatic and euthyroid. Physical examination was unremarkable. The thyroid ultrasonography showed a 1.4 × 1.0 cm hypoechogenic solid nodule with irregular borders and microcalcifications located in the right lobe. No cervical lymph nodules were found. Fine-needle aspiration of the nodule displayed a Bethesda VI category. Total thyroidectomy was performed. No lymph node dissection was implemented. During surgery, the thyroid parenchyma was diffusely black in color, increased in size, and multinodular. The patient was uneventfully discharged on postoperative day 1. Histopathology revealed a diffuse black discoloration of the specimen with a well-defined 1.2×0.8×0.6 cm nodule in the right upper lobe with features of classic papillary thyroid carcinoma. Recently the patient was seen at his 3-month follow-up, and there were no signs or symptoms of recurrence or metastasis. Clinical lessons: Although several studies describe a higher incidence of malignancy (being papillary thyroid carcinoma the most frequently associated) in black thyroid compared to non-black thyroid glands, a causal relationship has never been proven. Perhaps in this case the thyroid ultrasonography screening triggered the overdiagnosis and subsequently the overtreatment. Finally, having a "black organ" can be distressing for patients. Therefore, we should be meticulous in explaining "this disturbing fact". Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.