Longitudinal Change of Postoperative Serum Anti-thyroglobulin Antibody Levels in Patients Without Total Thyroidectomy and Remnant Ablation

Background: There is little information regarding postoperative thyroglobulin antibody (TgAb) changes in patients without a total thyroidectomy and ablation. This study aimed to analyze the longitudinal change of TgAb levels in patients with remnant thyroid.Methods: The study group were patients who had undergone a non-total thyroidectomy for a thyroid tumor from 1996 to 2018. The median follow-up period was 3.5 years (1–7.5 years). Eligible patients had a combined serum Tg and TgAb measurement at least three times biannually. We excluded patients with thyroid dysfunction at the initial diagnosis or with papillary carcinoma who had persistent or any recurrence of disease. Results: A total of 222 patients were enrolled. In the preoperative analysis, 42 (30%) patients had positive TgAb values, and 98 were negative (70%). Seventeen years after the operation, a TgAb value over 1000 IU/ml was not seen. The positive TgAb ratio was stable for 12 years (20%–30%); however, its positivity gradually increased from 13 years onward to 53.8%. The number of patients with consistently negative and positive TgAb values was 151 (68.0%) and 48 (21.6%), respectively. The number of patients with a mixture of positive and negative TgAb values was 10 (4.5%). The number of patients who changed from positive to negative values was six (2.7%) and, inversely, seven (3.2%). Conclusions: We found positivity of TgAb after surgery gradually increases over about 10 years in patients with normal remnant thyroid. We should measure both serum Tg and TgAb values concurrently for the patients with remnant thyroid tissue throughout.

The clinical significance of remnant thyroid tissue in thyroidectomized differentiated thyroid cancer patients on 131I-SPECT/CT

Background To explore the 131I-SPECT/CT characteristics of remnant thyroid tissue (RTT) in differentiated thyroid cancer (DTC), further assess the risk factors and clinical significance. Methods 52 DTC patients after total thyroidectomy had undergone neck 131I-SPECT/CT before 131I ablation. The diagnosis of RTT was based on SPECT/CT and follow-up at least 3 months. The anatomic locations and features of SPECT/CT of RTT were assessed by reviewers. The risk factors of RTT with CT positive were analyzed by the chi-square test. Results A total of 80 lesions of RTT were diagnosed in this study, most of them were mainly located in the regions adjacent to trachea cartilage (37/80) or lamina of thyroid cartilage (17/80). On SPECT/CT of RTT, low, moderate and high uptake were respectively noted in 10, 24 and 46 lesions, definite positive, suspected positive and negative CT findings were respectively noted in 10, 21 and 49. The RTT lesions with definite positive CT findings were mainly located adjacent to lamina of thyroid cartilage (5/10). Primary thyroid tumor (P = 0.029) and T stage (P = 0.000) were the effective risk factors of CT positive RTT. Conclusions RTT has certain characteristic distribution and appearances on SPECT/CT. Most of RTT with definite CT abnormalities located adjacent to lamina of thyroid cartilage, which suggest surgeons should strengthen the careful removal in this region, especially primary thyroid tumor involving bilateral and T4 stage. This study can provide a certain value for the improvement of thyroidectomy quality in DTC patients.

Iatrogenic Hyperthyroidism With Recurrent Functioning Thyroid Tissue 40 Years After Thyroidectomy for Graves’ Disease

Background: Graves’ disease is an immune-mediated cause of thyrotoxicosis treated with anti-thyroid drugs (ADTs), radioactive iodine (RAI) or thyroidectomy. Thyroidectomy has been documented to have the lowest rate of recurrence amongst treatment options1. Data regarding long-term recurrence rates is limited beyond 54 months. Clinical Case: An asymptomatic 59 year old female was found to have recurrent thyrotoxicosis on routine laboratory testing. The patient underwent thyroidectomy at age 19 years for Graves’ disease. Prior records unavailable to clarify initial surgical intervention. The patient had post-surgical hypothyroidism which was managed with levothyroxine 100mcg once daily for over 20 years. A biochemically euthyroid state was clearly documented on prior laboratory testing. Initial laboratory testing with TSH <0.01mIU/L (0.45-4.50), FT3 2.8ng/dL (0.8-1.7). Levothyroxine was discontinued with persistent thyrotoxicosis after 8 weeks: TSH <0.01, FT3 5.7, FT4 1.74. Radioactive Iodine Uptake and scan was obtained after administration of 6uCi of iodine-131 which demonstrated 50.8% uptake of radioactive iodine at 24 hours (Normal 10-30%). The left thyroid gland was noted to be in normal position and enlarged with diffuse increase intensity of radiotracer uptake. The right thyroid gland was surgically absent. The patient subsequently underwent completion thyroidectomy with endocrine surgery with resolution of hyperthyroid state. Surgical pathology was benign and consistent with Graves’ disease and multinodular goiter. The patient did become hypothyroid post-operatively and required levothyroxine replacement. She is clinically and biochemically euthyroid on levothyroxine 100mcg once daily 14 months post-operatively. Conclusion: This is a case of recurrent hyperthyroidism approximately 40 years after definitive treatment with thyroidectomy. Although it is unclear whether patient underwent total thyroidectomy or subtotal thyroidectomy for initial intervention, the recurrence of thyrotoxicosis after such a long period of time has not previously been reported in the literature to the knowledge of this writer. This has important implications regarding the underlying pathophysiology of Graves’ disease and the ability of remnant thyroid tissue to regenerate over time. This also has important implications for long-term monitoring in patients with history of thyroidectomy for Graves’ disease. Reference: 1. Sundaresh, V., Brito, J. P., Wang, Z., Prokop, L. J., Stan, M. N., Murad, M. H., & Bahn, R. S. (2013). Comparative effectiveness of therapies for Graves’ hyperthyroidism: a systematic review and network meta-analysis. The Journal of clinical endocrinology and metabolism, 98(9), 3671–3677.

Papillary Thyroid Microcarcinoma with Lung Metastases: A Case Report and Review of the Literature

Introduction: Distant metastasis from papillary thyroid microcarcinoma (PTMC) is rare. Here we report a case of PTMC with multiple lung metastases.Case Presentation: A 64-year-old man presented to our hospital with abdominal pain. Computed tomography incidentally revealed multiple lung nodules. The lung tumor was histologically diagnosed as metastasis of papillary thyroid carcinoma (PTC) by core needle biopsy via thoracoscopy. The patient was referred to our department for further examination. Neck ultrasonography revealed a 0.8 cm hypoechoic mass in the right lobe of the thyroid gland, diagnosed as PTC by fine-needle aspiration cytology. Subsequently, total thyroidectomy was performed, followed by radioiodine therapy. Iodine-131 (131-I) scintigraphy showed a strong accumulation in the lung metastasis. The patient presented no evidence of progression of lung metastasis for 25 months after the operation. Discussion/Conclusions: Although there are few published cases of metastatic PTMC, lymph node metastasis or extraglandular extension was observed in most patients, including the present case, and the average age of these cases was 58.8 ± 12.0 years. Although active surveillance without surgical resection is expected to remain standard of care for PTMC, this case indicates that a subset of PTMC patients with risk factors may develop distant metastases. Careful preoperative screening is required to avoid complications associated with reoperation of the remnant thyroid gland.

Using 2-dimensional color superb microvascular imaging vascularization index technique in the assessment of thyroid surgical bed

Aim: The purpose of this study was to investigate the effectiveness of the vascularization index (VI) obtained using color superb microvascular imaging (cSMI) technique in the assessment of thyroid surgical bed for remnant thyroid tissue (RTT). Material and methods: We evaluated the thyroid surgical bed of 65 patients who had underwent total thyroidectomy (TT) due to papillary carcinoma (PC) using thyroid scintigraphy and cSMI. Color SMI was also performed for the examination of the thyroid parenchyma of 39 healthy asymptomatic participants. VI measurements were performed by manually drawing the contours of the RTT in those with remnant thyroid, the thyroid surgical bed in the patients’ group without remnant thyroid, and normal thyroid parenchyma in the control group, using the free region of interest (ROI) with 2-dimensional color SMI VI (2DcSMIVI) mode. The volume of ROI was measured and echogenicity was evaluated. The quantitative 2DcSMIVI values of the surgical bed with RTT (Group A), the surgical bed without RTT (Group B) and normal thyroid of healthy asymptomatic participants (Group C) were compared. Results: The mean 2DcSMIVI values of Group A was significantly higher than Group B and C (p=0.001). The presence of RTT can be diagnosed with 89.1% sensitivity and 87.5% specificity when 1.75 2DcSMIVI is designated as the cut-off value. Conclusion: The 2DcSMIVI is an effective imaging technique that can be used for the diagnosis of RTT.

The Clinical Significance of Remnant Thyroid Tissue in Thyroidectomized Differentiated Thyroid Cancer Patients on 131I-SPECT/CT

BackgroundTo explore the 131I-SPECT/CT characteristics of remnant thyroid tissue (RTT) in differentiated thyroid cancer (DTC), further assess the risk factors and clinical significance. Methods 52 DTC patients after total thyroidectomy had undergone neck 131I-SPECT/CT before 131I ablation. The diagnosis of RTT was based on SPECT/CT and follow-up at least 3 months. The anatomic locations and features of SPECT/CT of RTT were assessed by reviewers. The risk factors of RTT with CT positive were analyzed by the chi-square test. Results A total of 80 lesions of RTT were diagnosed in this study, most of them were mainly located in the regions adjacent to trachea cartilage (37/80) or lamina of thyroid cartilage(17/80). On SPECT/CT of RTT, low, moderate and high uptake were respectively noted in 10, 24 and 46 lesions, definite positive, suspected positive and negative CT findings were respectively noted in 10, 21 and 49. The RTT lesions with definite positive CT findings were mainly located adjacent to lamina of thyroid cartilage (5/10). Primary thyroid tumor (P=0.029) and T stage (P=0.000) were the effective risk factors of CT positive RTT.Conclusion: RTT has certain characteristic distribution and appearances on SPECT/CT. Most of RTT with definite CT abnormalities located adjacent to lamina of thyroid cartilage, which suggest surgeons should strengthen the careful removal in this region, especially primary thyroid tumor involving bilateral and T4 stage. This study can provide a certain value for the improvement of thyroidectomy quality in DTC patients.

FACTORS INFLUENCING THE SUCCESSFUL MAINTENANCE OF EUTHYROIDISM AFTER LOBECTOMY IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA: A SINGLE-CENTER STUDY

Objective: This study aimed to evaluate factors influencing the successful maintenance of postoperative euthyroidism in patients who did not undergo immediate thyroid hormone replacement after lobectomy for papillary thyroid microcarcinoma (PTMC). Methods: From September 2015 to June 2017, 186 patients underwent lobectomy for PTMC in our hospital. Patients taking medications for hypothyroidism and hyperthyroidism before and after lobectomy were excluded. Multiple parameters, including sex, age, pre-operative free thyroxine (T4), thyroid-stimulating hormone (TSH), thyroglobulin (TG), and thyroid autoantibody levels, body mass index (BMI), postoperative histopathology of the thyroid gland, remnant thyroid gland volume, and session number of levothyroxine discontinuation were retrospectively evaluated. These factors were compared between groups based on the maintenance of postoperative euthyroidism. Results: In 88 of the 175 patients (50.3%), postoperative euthyroidism was successfully maintained without thyroid hormone replacement during the first year after lobectomy. There were significant differences in sex ( P = .003), pre-operative TSH levels ( P = .002), and histopathology of the thyroid gland ( P = .035) between the groups showing maintenance success and failure. The group showing successful maintenance had a higher percentage of male patients, lower levels of pre-operative TSH, and normal parenchymal histology of the thyroid gland. However, there were no significant between-group differences in age, pre-operative free T4, TG, and thyroid autoantibody levels, BMI, remnant thyroid gland volume, and session number of levothyroxine discontinuation. Conclusion: Patient sex, pre-operative TSH levels, and histopathology of the thyroid gland may influence the maintenance of postoperative euthyroidism after lobectomy. Abbreviations: BMI = body mass index; PTMC = papillary thyroid microcarcinoma; RR = reference range; T4 = thyroxine; TFT = thyroid function test; TG = thyroglobulin; TSH = thyroid-stimulating hormone