Radio Frequency Ablation of Enlarged Thyroid Nodules: A Case Report.

Simple SummaryUltrasound (US)-guided minimally-invasive techniques, such as radiofrequency ablation (RFA) have emerged as an alternative treatment to surgery for benign and malignant thyroid nodules. Based on a systematic literature search, here we report the long-term outcomes of thyroid RFA. Available data show that US-guided RFA significantly reduced benign thyroid nodules and destroyed most PTMC, and this was generally maintained for at least 5 years after the initial treatment. Further studies addressing the risk of regrowth in patients with benign thyroid nodules, as well as the risk of recurrence in patients with PTMC are needed.Background: US-guided minimally-invasive techniques, such as radiofrequency ablation (RFA) have emerged as an alternative treatment for benign and malignant thyroid nodules. This systematic review aims to provide an overview on the long-term outcomes of US-guided RFA in patients with benign and malignant thyroid nodules. Methods: We systematically searched PubMed/MEDLINE, EMBASE, and Scopus to identify articles reporting the outcomes of thyroid RFA after a follow-up of at least 3 years. Results: A total of 20 studies met the inclusion criteria and were included in the review. In patients with benign thyroid nodules, RFA significantly reduced nodule volume and this was generally maintained for the following 5 years. However, a small but not negligible proportion of nodules regrew and some of them required further treatments over time. In patients with malignant nodules, RFA has been used not only to treat differentiated thyroid cancer (DTC) neck recurrences, but also to treat papillary thyroid microcarcinoma (PTMC). In most patients with PTMC, RFA led to complete disappearance of the tumor. When it was compared to surgery, RFA was not inferior in terms of oncologic efficacy but it had a lower complication rate. However, RFA did not allow for final pathology, disease staging and accurate risk stratification. Conclusions: US-guided RFA significantly reduces benign thyroid nodules and destroys most PTMC, and this is generally maintained for at least 5 years after the initial treatment. Further studies addressing the risk of regrowths in patients with benign thyroid nodules, as well as the risk of recurrence in patients with PTMC are needed.

Objective:We aimed to evaluate the clinical, radiological and pathological findings of children and adolescents with thyroid nodules.Methods:Data of 121 children and adolescent with thyroid nodules and had fine needle aspiration (FNA) were examined retrospectively. Concomitant thyroid disease, ultrasonography (US) features of the nodule, FNA and histopathological results were recorded. FNA results were assessed according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).Results:Median (range) age of the cases was 14 (3-18) years and 81% were female. FNA results of patients were: insufficient in 1 (0.8%); benign in 68 (56.2%); indeterminate in 44 (36.4%); and malignant in 8 (6.6%) patients. Among 39 patients who underwent surgery, 10 (25.6%) had differentiated thyroid cancer (DTC) and the overall malignancy rate was 10.0% (10/100). Follow-up FNA results showed progress based on TBSRTC in 18.7% of benign results and 4/75 patients had DTC on surgical excision. Two of 22 patients with atypia of undetermined significance (AUS) who continued follow-up was diagnosed with DTC. Male gender, presence of Hashimoto thyroiditis and US findings of uninodularity, hypoechogenicity, increased blood flow, irregular margins, solid structure, microcalcification and presence of abnormal cervical lymph nodes were associated with malignancy.Conclusion:In this study 10% of thyroid nodules were malignant in children and adolescents. Patients with AUS have a 9% potential for malignancy. Patients with initially benign FNA result may have changes on repeat FNA when assessed with TBSTRC indicating a 5.3% false negative rate.

Background Cytological examination of the material obtained by fine-needle aspiration (FNA) is the best single test for differentiating malignant from benign thyroid nodules. In 2007, the British Thyroid Association introduced the ‘Thy’ classification for FNA of the thyroid to help in the management of the thyroid nodule. They suggested a plan of management for each of the Thy I to Thy V results. Aim The aim of this study was to analyze the outcomes for all Thy III results from FNA and to detect the rate of malignancy in them. Patients and methods This was a prospective study that included 24 patients who had Thy III results from fine-needle cytology. The patients were reviewed, analyzed, and operated (either lobectomy or total thyroidectomy) according to distribution of thyroid nodules. Then histopathological examination of the removed thyroid tissue was done. Results All patients in the study were reported as having Thy III in thyroid FNA. Thy IIIA was reported in six (25%) patients and the other 18 (75%) cases were categorized as having Thy IIIF. Overall, eight (33.3%) patients had right hemithyroidectomy and four (16.7%) patients had left hemithyroidectomy, whereas 12 (50%) patients had total thyroidectomy. A total of 11 (45.8%) patients were recorded as having multinodular goiter, two (8.3%) patients had nodular goiter with lymphocytic thyroiditis, seven (29.2%) patients had follicular adenoma, two (8.3%) patients were recorded as having follicular carcinoma, and two (8.3%) patients had papillary thyroid carcinoma. Conclusion Thy IIIF had a higher incidence of malignancy than Thy IIIA with a high statistically significant difference (P=0.53). It is, therefore, evident that Thy III results from FNA of the thyroid have a high risk of being malignant, but there still is a controversy regarding how to manage them, which leads to delay in treatment.

Serum thyroglobulin (Tg) is a critical marker for monitoring tumor recurrence and metastasis in patients who have undergone total thyroidectomy for differentiated thyroid cancer (DTC). While the definitive role of preoperative serum Tg in DTC is not yet established, studies suggest its importance in differentiating between benign and malignant thyroid nodules with indeterminate cytology, as well as in predicting distant metastasis (DM) in patients with DTC. A thorough literature review was conducted on the use of preoperative serum Tg in differentiating between benign and malignant thyroid nodules, and in evaluating the extent of DTC lesions. Relevant studies were systematically searched in PubMed, Embase, Cochrane, Scopus, and ClinicalTrials databases. A meta-analysis was performed on studies where the ratios between serum Tg diagnostic thresholds and the upper limit of the reference range were similar. Recent studies showed significantly elevated preoperative serum Tg levels in patients with DTC compared with normal individuals. However, there are inconsistencies in the serum Tg levels between patients with preoperative DTC and benign thyroid nodules across different studies. In patients with thyroid nodules who had indeterminate cytology (negative Tg antibody), the preoperative serum Tg levels were significantly higher in malignant nodules than in benign ones (meta-analysis: odds ratio: 2.59, 95% confidence intervals: 1.59-4.21, P = 0.0001). Although the meta-analysis indicated that high preoperative serum Tg is a risk factor for central lymph node metastasis in patients with DTC (meta-analysis: odds ratio: 1.68, 95% confidence interval: 1.32-2.14, P < 0.0001), some studies suggest that high preoperative serum Tg in patients with DTC does not necessarily lead to central lymph node metastasis. Furthermore, preoperative serum Tg might possess a suggestive value regarding the likelihood of DTC patients developing DM. Preoperative serum Tg shows promise in differentiating between benign and malignant nodules in thyroid nodule patients with indeterminate cytology. However, further research is necessary to determine its predictive significance for lymph node metastasis and DM in patients with DTC. https://www.crd.york.ac.uk/PROSPERO/#searchadvanced, identifier CRD42024472074.

Thyroid hyperplasia/multinodular goiter, characterized by cellular and follicular overgrowth, is a very common endocrine condition, resulting in various functional and structural consequences and certain malignant potential. Its genetic background is completely unknown. Given previous genetic and epigenetic data suggesting that RASAL1 might be a thyroid tumor suppressor gene, particularly in follicular thyroid neoplasm, we hypothesized that the RASAL1 gene could play a fundamental role in the development of thyroid hyperplasia/multinodular goiter. To explore the role of the RASAL1 gene in the development of thyroid hyperplasia/multinodular goiter, we developed a novel Rasal1 knockout mouse model using the CRISPR/Cas9 approach and the C57BL/6J zygotes, followed by observing the pathological changes in the thyroid gland of the knockout mice in comparison with the wildtype mice. We successfully created a novel Rasal1 knockout mouse model with establishment of several generations of mice carrying the heterozygous and homozygous knockout of the Ra-sal1 gene at exon 2, which was confirmed by genetic testing and by Western blotting of the Rasal1 protein. All the mice with Rasal1 knockout, whether heterozygous or homozygous, developed grossly visible multinodular goiter with microscopic confirmation of follicular cell hyperplasia, with occasional case showing thyroid cancer. In contrast, only occasional case of aged wild-type mice developed thyroid hyperplasia and no wild-type mice developed thyroid malignancy. These data demonstrate that defect of Rasal1 can cause full and complete development of thyroid hyperplasia/multinodular goiter in mice. Given the striking similarity of thyroid hyperplasia/multinodular goiter in these Rasal1 knockout mice with that in humans, it is plausible to suggest that RASAL1 is a master gene involved in the development and pathogenesis of human thyroid hyperplasia/ multinodular goiter. This project also provides a new genetic knockout mouse model for future study of thyroid neoplasm.

Low cellularity can be problematic in thyroid fine needle aspiration (FNA) biopsies. The Cellient cell block (CB) system has been reported to improve cell recovery compared to traditional methods. Therefore, we studied the utility of Cellient CBs in the evaluation of thyroid FNAs, with an emphasis on low-cellularity specimens. ThinPrep slides were prepared from thyroid FNAs submitted in Cytolyt. After assessment using TBSRTC criteria, Cellient CBs were requested on samples with residual FNA material and an initial cytologic impression of non-diagnostic, AUS/FLUS, and on apparently benign samples with marginally adequate cellularity. The contribution of the CB findings to the final diagnosis was assessed. 965 cases of paired ThinPrep and CB sections were examined. Overall, the cell block findings resulted in a change of the initial ThinPrep impression in 15% (n = 148) of cases. The vast majority of these changed cases were initially inadequate for interpretation, and specifically, 31% (n = 123) of the non-diagnostic ThinPrep samples became diagnostic with a CB. The cell block findings contributed to a change in diagnosis in 8% (n = 23) of AUS/FLUS cases, and in less than 1% of low-cellularity benign samples. The use of CBs in low-cellularity thyroid FNAs has not been well described. In this study, we found that the contribution of CBs in this setting varied by TBSRTC category. Specifically, the samples that benefited most were initially non-diagnostic specimens and select cases of AUS/FLUS, while low-cellularity benign samples gained very little additional information. Diagn. Cytopathol. 2016;44:737-741. © 2016 Wiley Periodicals, Inc.

BackgroundThe aim of this study was to compare the results of palpation-versus ultrasound-guided thyroid fine-needle aspiration (FNA) biopsies.FindingsClinical data, cytology and histopathology results were retrospectively analyzed on all patients who underwent thyroid FNA biopsy in our outpatient endocrinology clinic between January 1998 and April 2003. The same investigators performed all thyroid FNAs (ASC) and cytological evaluations (KP). Subjects in the ultrasound-guided group were older, otherwise there were no differences in baseline characteristics (gender, thyroid function, the frequency of multinodular goiter, nodule diameter and nodule location) between groups. Cytology results in nodules aspirated by palpation (n = 202) versus ultrasound guidance (n = 184) were as follows: malignant 2.0% versus 2.7% (p = 0.74), benign 69.8% versus 79.9% (p = 0.02), indeterminate 1.0% versus 4.9% (p = 0.02), inadequate 27.2% versus 12.5% (p < 0.01). Malignant results were compared with Fisher's exact test. Other cytology categories were compared with chi-square test. Eighteen patients from the palpation- and 23 from ultrasound-guided group underwent surgery. In the palpation-guided group, the sensitivity of FNA was 100%, specificity 94%, positive predictive value 67% and negative predictive value 100%. In the ultrasound-guided group, the sensitivity of FNA was 100%, specificity 80%, positive predictive value 73% and negative predictive value 100%.ConclusionWe demonstrate that ultrasound guidance for thyroid FNA significantly decreases inadequate for evaluation category. We also confirm the high sensitivity and specificity of thyroid FNA biopsy in the diagnosis of thyroid cancer. Where available, we recommend universal application of ultrasound guidance for thyroid FNA biopsy as a standard component of this diagnostic technique.

Thyroid cancer occurred in approximately 45,000 patients, in the USA in 2010. There is a 3:1 ratio of women to men. Histologic types are divided into categories of differentiated thyroid cancer (DTC): papillary, mixed papillary and follicular, and follicular—including Hurthle cell variant, undifferentiated (anaplastic), and medullary cancer (arising from parafollicular C-cells). Other rare thyroid carcinoma accounts non-epithelial tumors, lymphoma and carcinomas characterized by the presence of mucin-producing cells and keratin. Differentiated thyroid cancer usually presents as a thyroid nodule. Thyroid ultrasonography is useful to detect and characterize thyroid nodules, as well as guide fine needle aspiration (FNA) biopsy. Radioiodide or 99mTc-pertechnetate thyroid scan has a low diagnostic specificity and sensitivity for characterizing thyroid nodules. X-ray of the neck is useful to disclose a deviation of the trachea or lumen restriction, in large nodules and in multinodular goiter. CT or MRI are generally reserved for mediastinal thyroid masses, or the identification of regional or distant metastasis. The most widely used staging system for thyroid carcinoma is the TNM classification system defined jointly by the UICC and by AJCC. 131I-iodide thyroid remnant ablation is indicated in differentiated thyroid cancer patients with a moderate to high likelihood of recurrence. 131I-iodide therapy is usually administered in the amount of 1.85 to 3.7 GBq for ablation. Patients are prepared with rhTSH and low iodine diet. Whole body scan (preferably with SPECT/CT of the neck) is performed 4–7 days after radioiodine therapy to detect lymph node involvement or unexpected metastases. The major diagnostic modalities employed to follow patients with differentiated thyroid cancer treated with remnant ablation is measurement of serum Tg, 131I-WBS, and neck US examination. Neck US examination is an integral component of follow-up evaluation in all DTC patients. If a lymph node metastasis is suspected, an FNA should be performed. Serum Tg levels that become detectable upon TSH stimulation indicate the need for further evaluation, possibly with additional radioiodine therapy. Although CT and MRI can in principle localize very small lesions in the neck, chest, and bones, the features of such lesions are rarely specific for recurrent/metastatic DTC. Patients with recurrent thyroid cancer may develop lesions which cannot concentrate radioiodide. [18F]FDG PET/CT is useful in these patients to determine the sites and extent of these metastases. The anaplastic thyroid carcinoma (ATC) is a rare tumor (<3% of all thyroid cancers) with poor prognosis derived from follicular cells. The most clinical presentation of an ATC is a new, large, firm thyroid nodule, often associated with signs/symptoms of local compression/invasion. Multimodality treatment of ATC includes surgery, EBRT, and combination chemotherapy. Therapy with 131I-iodide is not useful, since these tumors rarely concentrate radioiodide. Preoperative imaging with US, CT, MRI play an important role, and [18F]FDG PET is useful. Medullary thyroid carcinoma (MTC) is a well-differentiated thyroid tumor arising from the parafollicular, calcitonin-producing C cells. Its prevalence is 5–10% in all thyroid malignancies. Sporadic and familial forms are recognized. Elevated baseline serum levels of calcitonin (above 10 ng/mL) are diagnostic for MTC. Following surgery, MTC patients are monitored with serum calcitonin and CEA levels, and serial neck US examinations are performed. Calcitonin doubling time in serum is the most sensitive biomarker for MTC progression. Scintigraphy with 123I-MIBG has very high sensitivity for staging patients with MEN II and familial MTC. However, it has a low sensitivity in patients with increased serum calcitonin but no clinical site of disease. [18F]FDG PET is accurate in detecting lymph node involvement. Radionuclide therapy with the radiolabeled somatostatin analog 90Y-DOTA-Tyr3-octreotide (90Y-DOTA-TOC) has been tested in metastatic MTC. Parathyroid carcinoma is a very rare endocrine malignancy that occurs in <1% of primary HPTH. The initial clinical manifestations of parathyroid carcinoma are primarily linked to the effects of markedly elevated serum PTH levels. At initial presentation, very few patients have metastasis at regional lymph nodes or at distant sites. Parathyroid carcinoma tends to infiltrate adjacent structures in the neck. US, CT, and MRI have been used to localize parathyroid carcinomas and to detect mediastinal and thoracic recurrences or distant metastases. 99mTc-Sestamibi scintigraphy can be successful for preoperative localization of the neoplasia and can identify metastases in lymph nodes and at distant sites. PET with [18F]FDG can also detect metastatic parathyroid cancers. Parathyroid carcinoma recurs in more than 50% of the cases and imaging studies should be performed in all patients before reoperation.

Nodular thyroid disease is a very common finding in clinical practice, discovered by ultrasound (US) in about 50 % of the general population, with higher prevalence in women and in the elderly [1–4]. Whereas therapeutic flowchart is quite established and shared for malignant lesions, multiple options are now available for patients presenting with benign thyroid nodules, ranging from simple clinical and US follow-up to thyroid surgery. The majority of thyroid nodules, benign by fine-needle aspiration, are asymptomatic, stable, or slow-growing over time and require no treatment. Nevertheless, large thyroid nodules may become responsible for pressure symptoms, resulting in neck discomfort, cosmetic complaints, and decreased quality of life. Partial/total thyroid surgery has so far constituted the only therapeutic approach for these. Although surgery is widely available, highly effective, and safe in skilled centers, complications (both temporary and permanent) still occur in 2–10 % of cases [5, 6]. Hypothyroidism is an unavoidable effect after total thyroidectomy, requiring lifelong l-thyroxine replacement therapy. Besides, surgery is expensive and may be not recommended for high-risk patients or refused by others. Radioiodine (131I) therapy has been proven to be effective to treat toxic multinodular goiters and autonomously functioning thyroid nodules (AFTN) [7], although they are usually more radioresistant than toxic diffuse goiters [8]. Radioiodine therapy normalizes thyroid function and significantly reduces thyroid volume. However, hypothyroidism often occurs, in up to 60 % of patients, several years after treatment [9]. Otherwise, radioiodine therapy shows only incomplete, weak effects in nonfunctioning cold thyroid nodules. Pretreatment with recombinant human TSH may improve goiter volume reduction by causing a more homogeneous distribution of radioiodine within the gland, especially increasing the uptake of 131I in scintigraphically relatively cold areas [10]. TSH-suppression therapy withl-thyroxine was widely used to achieve nodule shrinkage and to prevent nodule growth and formation, producing, however, controversial results and exposing patients to heart and bone side effects. Therefore, current guidelines do not recommend its routine use in clinical practice, suggesting its usefulness in some cases only [3, 4]. Over the last two decades, nonsurgical, minimally invasive, US-guided techniques have been proposed for the treatment of thyroid nodules [11–16]. Percutaneous ethanol injection (PEI) is recommended for the treatment of relapsing cysts and dominantly cystic thyroid nodules [17]. Because of the limitations of PEI in the management of solid thyroid nodules, hyperthermic methods (laser ablation and radiofrequency ablation) have been introduced afterward for the treatment of solid, benign thyroid lesions [18], achieving marked nodule size reduction and clinical improvement in nodule-related symptoms, in several series from skilled centers, especially in Korea and Italy. Other nonsurgical therapies, such as high-intensity focused-ultrasound (HIFU), microwaves, cryotherapy, and electroporation, are presently under investigation.

American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules

Background: The Coronavirus disease 2019 (COVID-19) pandemic impacted health care systems in all countries, including Qatar. Hamad Medical Corporation (HMC); In compliance with recommendations, suspended all non-urgent procedures, including thyroid fine needle aspiration biopsies (FNAB). Thyroid nodules are second most common cause of referral to HMC endocrine clinic. FNABs are gold standard to differentiate benign from malignant nodules.1- 2Methods: Our approach includes a teleconsultation to obtain patient’s history and risk factors. Reviewing neck ultrasound (US), obtaining a calcitonin level if indicated, considering comorbidities associated with a high risk of COVID-19 morbidity and mortality.3Results: We developed a pathway triaging thyroid (FNAB) to:1-Urgent: patients at higher risk of aggressive thyroid malignancy. Benefits of early detection and treatment outweigh the risk of COVID-19 exposure.4 FNAB should not be delayed.2-Semi-urgent: patients at low risk for COVID-19 and high suspicion thyroid nodules, but no evidence that early detection improves survival2, FNAB may be delayed up to 12 months.3-Non-urgent: patients with asymptomatic nodules that have low or intermediate suspicion US pattern.2 Also, includes nodules with ATA high suspicion US pattern in pregnant women and patients at high risk for COVID-19. The risks outweigh the benefits. FNAB should be delayed until outbreak is controlled.4 When urgent FNAB is indicated, safety of patients and medical staff needs to be addressed.5 We recommend testing patient for COVID-19 before FNAB, utilizing US guidance with rapid on-site adequacy evaluation in all cases. Cervical lymph node FNAB with TG washout should be done if indicated. The patient should wear a mask. All medical staff involved should wear personal protective equipment (PPE). The operator should wear N95 mask and face shield. The patient should be informed about cytopathology results via telemedicine.Conclusion: Triaging thyroid (FNAB) during the COVID-19 pandemic should be based on nodule characteristics and risk of COVID-19 morbidity and mortality. Our group recommends deferring FNAB for asymptomatic patients.4FNAB should not be delayed in selected patients who benefit from early detection and intervention.Table1: Triage of Thyroid fine needle aspiration biopsies (FNAB). ATA: American thyroid association. US: ultrasound.

Background The global prevalence of multinodular goiter is high, with most cases occurring in developing countries. In recent literature, the incidence of differentiated thyroid carcinoma among patients with multinodular goiter has risen. Objectives To ascertain the prevalence of differentiated thyroid cancer in patients with multinodular goiter. Patients and method: This cross-sectional study was done in a teaching hospital in Sulaimani, Iraq, to determine the frequency of differentiated thyroid cancer in 64 patients with multinodular goiter admitted to the surgical ward from Feb 1, 2021, to Jan 31, 2023. A history and clinical examination, a fi ne needle aspiration, and a postoperative histopathology examination were performed to confi rm the diagnosis. Results The mean age was 39.4 years old with ± SD 11.2; more than half of the participants were between 30 and 50 (53.1%) and older than 50 (37.5%). Females were predominant at 53/64 (82.8%). 31.25% of the multinodular goiter patients had differentiated thyroid carcinoma by histopathology, while it was 21% by fi ne needle aspiration. The histopathology of multinodular goitre patients revealed that 68.75% had endemic goitre, 12 (18.75) had papillary carcinoma, and 6 (9.375) had follicular thyroid carcinoma. Smoking and older age were associated with differentiated thyroid carcinoma in patients with multinodular goiter. Conclusion With a high proportion of malignancy among multinodular thyroid goiter participants according to FNA and histopathology, the fi ne needle aspiration test result was a low-accurate tool for differentiated thyroid carcinoma diagnosis associated with multinodular goiter

Background Thyroid fine needle aspiration (FNA) is the mainstay for diagnosis of malignancy, and is an integral part of current thyroid nodule assessment. The present study analyzes the diagnostic accuracy of palpation-directed versus ultrasound guided fine-needle aspiration in patients who underwent surgery for thyroid nodules. Methods A retrospective chart review of all consecutive patients who had FNA biopsy (palpation or ultrasound guided) of thyroid nodules and underwent thyroid gland surgery between 1998 and 2014 was conducted. The FNA findings of the palpation-guided and ultrasound-guided groups were compared for baseline characteristics. Moreover, the diagnostic accuracy of FNA findings and surgical histopathology results were analyzed. Results A total of 1174 patients were included in the study with a mean age of 46.3 ± 11.7 years and the majority were females (75.5%). Among the study population, 392 (33.4%) patients underwent US-guided FNA; 570 (48.6%) had palpation-guided FNA in clinic and no FNA was done in 212 (18%) cases. Patients underwent US-guided FNA were more likely to have suspicion of malignancy (p = 0.001), and had indeterminate findings (p = 0.001). On the other hand, palpation-guided FNA group had significantly higher frequency of benign cytology (p = 0.001). With respect to the suspicion for malignancy as well as malignancy, the US-guided group had a similar diagnostic accuracy in comparison to the palpation group. The proportion of malignancy finding on US-guided FNA (8.9%) was higher than the palpation-guided FNA (6.4%) that had been confirmed on postoperative histopathological examination (p = 0.95). Conclusion The present study demonstrates higher sensitivity of US-guided thyroid FNA biopsies over palpation-guided FNA for the suspicion of malignancy; however, the accuracy is comparable. Moreover, both groups showed more postoperative malignancy in the benign and unsatisfactory categories than predicted in the Bethesda system. Further prospective studies are needed to underpin a realistic correlation between FNA and final histopathology reports.

The scintigraphic findings in Hashimoto's thyroiditis are highly variable and can mimic any thyroid abnormality. In this study, we compared the scintigraphic findings with ultrasonography in 48 patients with Hashimoto's thyroiditis. Thyroid scintigrams revealed diffuse hyperplasia in 12 patients, multinodular goiter in 20 patients and a solitary nodule in 16 patients (toxic adenoma, n = 1; hypoactive nodule, n = 4; hyperactive nodule with no suppression, n = 3; normoactive nodule, n = 8). Ultrasonography revealed diffuse hyperplasia in 19 patients, multinodular goiter in 20 patients and a solitary nodule in 9 patients. The thyroid scan and ultrasonography revealed the same findings of diffuse hyperplasia in 12 patients and multinodular goiter in 20 patients. Of the 16 patients with a solitary nodule on scintigraphy, only 9 showed the same finding on ultrasonography, with the other 7 showing diffuse hyperplasia. The difference in nodularity between thyroid scanning (74.9%) and sonography (60.4%) has been attributed to pseudonodularity in Hashimoto's thyroiditis. In conclusion, our results confirmed that Hashimoto's thyroiditis can mimic any thyroid abnormality, including diffuse hyperplasia, nodular goiter and multinodular goiter on scintigraphy. Therefore, scintigraphy, ultrasonography and serum thyroid hormone estimation alone may not be helpful for the final diagnosis of Hashimoto's disease. To eliminate unnecessary surgical intervention, all patients should be evaluated by means of physical examination and thyroid autoantibodies, in addition to a thyroid scan, ultrasonography, serum thyroid hormones and fine-needle aspiration biopsy when necessary.

The HiLo Trial: a Multicentre Randomised Trial of High- versus Low-dose Radioiodine, with or without Recombinant Human Thyroid Stimulating Hormone, for Remnant Ablation after Surgery for Differentiated Thyroid Cancer