Use of Methotrexate to Treat Isolated Graves Ophthalmopathy Developing Years After Thyroidectomy and Iodine 131 Treatment of Papillary Thyroid Cancer

ObjectiveTo describe a case of Graves ophthalmopathy developing years after subtotal thyroidectomy and radioactive iodine treatment of papillary thyroid cancer.MethodsWe present a case report including clinical and laboratory data. Current relevant literature is reviewed and summarized with regard to Graves ophthalmopathy.ResultsIn 2001, a 51-year-old woman presented with an asymptomatic thyroid nodule. Fine-needle aspiration biopsy results showed Hürthle cells, and the patient had a subtotal thyroidectomy in 2002. Stage 2 follicular variant of papillary thyroid carcinoma was diagnosed. She received radioactive iodine (I 131) therapy (94.8 mCi and 147.2 mCi) in 2003. Thyrotropin was suppressed with levothyroxine. The patient remained asymptomatic and had undetectable thyroglobulin antibodies. In 2007, her eyes became irritated (ie, erythematous, pruritic, watery). Thyroperoxidase and thyroglobulin antibodies were undetectable, but thyrotropin receptor antibody was elevated to 44% (reference range, < 16%). On physical examination, moderate periorbital edema and conjunctival injection were present; orbital magnetic resonance imaging was normal. Computed tomography of her orbits showed symmetric bilateral exophthalmos and prominence of orbital fat. Other ophthalmologic etiologies were ruled out by 2 independent ophthalmologists. She had minimal improvement with oral and intravenous steroids. Subsequent treatment with methotrexate resulted in marked symptomatic improvement and lowered the thyrotropin receptor antibody level to 24%.ConclusionsIsolated Graves ophthalmopathy in a patient after treatment of thyroid cancer and radioactive iodine ablation has not been previously reported. Methotrexate therapy may be a useful therapeutic approach in this setting. (Endocr Pract. 2008;14:422-425)     

Long-Term Follow-Up of a Patient With Papillary Thyroid Carcinoma,Elevated Thyroglobulin Levels,and Negative Imaging Studies

ObjectiveTo describe a patient with papillary thyroid carcinoma who had measurable thyroglobulin (Tg) levels for 20 years without clinical or imaging evidence of a malignant lesion.MethodsWe reviewed the clinical course, pathologic findings, Tg measurements, and results of various imaging studies in our patient and reviewed the literature regarding Tg-positive, diagnostic total-body radioiodine scan-negative patients with thyroid cancer.ResultsFour months after a 3.5- by 3.5-cm follicular thyroid cancer was removed from the anterior neck area of a 5-year-old girl, a bilateral subtotal thyroidectomy was performed. At age 12 years, she presented with a 2-cm mass on the right side of the neck. After a completion thyroidectomy, recurrent mixed papillary-follicular thyroid cancer was found scattered throughout the remaining thyroid parenchyma. Although a postoperative diagnostic total-body radioiodine scan did not reveal uptake of ¹³¹I, the Tg level was 58 ng/mL. Despite Tg levels as high as 2,528 ng/mL, the patient had no clinical evidence of thyroid cancer during a 20-year period of follow-up. Moreover, numerous imaging studies, including total-body scanning after the administration of 150 mCi of ¹³¹I and [¹⁸F]fluorodeoxyglucose positron emission tomography, were negative. Review of pathologic specimens from both operations with use of updated diagnostic criteria indicated that the tumor was a papillary thyroid carcinoma.ConclusionOur observations and the observations of other investigators indicate that some thyroid cancers produce Tg so efficiently that high levels of Tg may be associated with tumors that remain too small to be detected by imaging studies. The Tg levels may remain stable, decline, or even disappear over time without treatment. (Endocr Pract. 2005;11:43-48)     

Prognostic Value of Lymph Node Uptake on Pretreatment F-18 FDG PET/CT in Patients with N1B Papillary Thyroid Carcinoma

Objective: The aim of this study was to investigate the prognostic value of metabolic characteristics of metastatic lymph node (LN) using pretreatment F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for patients with papillary thyroid carcinoma (PTC) and metastatic lateral LN (N1b).Methods: Ninety-six PTC patients (female:male = 72:24; median age, 44.5 years) with pathologic N1b who underwent pretreatment FDG PET/CT, total thyroidectomy, and radioactive iodine ablation were retrospectively reviewed. To predict responses to initial therapy and recurrence, clinicopathologic factors and metabolic parameters were reviewed, such as sex, age, tumor size, extranodal extension, number and ratio of metastatic LNs, serum thyroglobulin, and maximum standardized uptake value (SUVmax).Results: Among the 96 PTC patients, 81 (84.4%) were classified into the acceptable response (58 excellent; 23 indeterminate) and 15 (15.6%) into the incomplete response (8 biochemical incomplete; 7 structural incomplete) by the 2015 American Thyroid Association management guideline for differentiated thyroid carcinoma. The multivariate analysis showed that SUVmax of N1b (P = .018), pre-ablation stimulated thyroglobulin level (P = .006), and the ratio of metastatic LNs (P = .018) were related to incomplete response. The cutoff value of each variable was determined by receiver operating characteristic analysis. Nine (9.4%) patients experienced recurrences (median follow-up: 50 months). The Kaplan-Meier analysis revealed that SUVmax of N1b (cutoff value: 2.3; P = .025) and ratio of metastatic LNs (cutoff value: 0.218; P = .037) were significant prognostic factors for recurrence.Conclusion: High SUVmax of N1b cervical LN on pretreatment FDG PET/CT could predict incomplete responses to initial therapy and recurrence in patients with N1b PTC.Abbreviations: ATA = American Thyroid Association; DTC = well-differentiated thyroid carcinoma; FDG = F-18 fluorodeoxyglucose; IQR = interquartile range; LN = lymph node; N1b = metastatic lateral cervical lymph node; PET/CT = positron emission tomography/computed tomography; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SUVmax = maximum standardized uptake value; Tg = thyroglobulin; USG = ultrasonography     

Thyrotoxicosis due to Ectopic Lateral Thyroid Tissue Presenting 5 Years After Total Thyroidectomy

ObjectiveTo describe a patient who, 5 years after total thyroidectomy to treat Graves disease, presented with thyrotoxicosis due to nonmalignant lateral ectopic thyroid tissue.MethodWe describe the laboratory, imaging, and physical findings of the study patient and review the relevant literature.ResultsA 32-year-old white woman with a history of Graves disease presented with recurrent hyperthyroidism 5 years after total thyroidectomy. A radioactive iodine scan was performed, which revealed elevated uptake (40%) and positive imaging in the left mid-neck. Ultrasonography examination of the neck confirmed the absence of any thyroid tissue within the thyroid bed, but documented 2 nodular, hypoechoic left upper-neck masses with punctuate hyperlucency. Contrast-enhanced computed tomography was performed to precisely localize the nodules, which were excised surgically via selective neck dissection. Histopathologic examination revealed chronic lymphocytic inflammatory infiltrate with focal thyroid hyperplasia and papillary infoldings and no evidence of malignancy.ConclusionsTo our knowledge, this represents the first report of ectopic benign thyroid tissue as the sole cause of hyperthyroid symptoms, and this entity should be considered in patients who have undergone thyroidectomy and have persistent hyperthyroidism. (Endocr Pract. 2011;17:70-73)     

Graves Ophthalmopathy After Radiation Treatment of Thyroid Cancer

ObjectiveTo describe a patient with metastatic thyroid cancer who developed Graves ophthalmopathy after treatment with radioiodine (I 131) and external beam radiation.MethodsWe present a case report that includes clinical, laboratory, and radiologic findings and a brief review of the literature.ResultsA 49-year-old woman who had had a total thyroidectomy and neck dissection followed by I 131 treatment 5 years earlier for papillary thyroid cancer presented for follow-up management after recent neck dissection for recurrent disease. Because she had thyroglobulin antibodies, she was again treated with I 131 after preparation with recombinant human thyroid-stimulating hormone. A post-treatment scan revealed uptake in the right iliac crest. A fludeoxyglucose F 18 positron emission tomography/computed tomography fusion scan revealed osseous metastases in the right pelvis, and external beam radiotherapy was delivered to this area. Approximately 5 months later, she developed periocular swelling and excessive tearing. Magnetic resonance imaging of the orbits revealed enlargement of the extraocular muscles. Serum thyroid-stimulating immunoglobulins were greatly elevated.ConclusionThis case corroborates an earlier report to suggest that radiation-associated thyroid injury in a patient with thyroid cancer may be followed by Graves ophthalmopathy and appearance of thyroid-stimulating immune-globulins in the serum. (Endocr Pract. 2008;14:419-421)     

L’apport de l’imagerie hybride TEMP/TDM dans la prise en charge du cancer différencié de la thyroïde

IntroductionSingle photon emission computed tomography combined with a low dose computed tomography (SPECT/CT), is a hybrid imaging integrating functional and anatomical data. The purpose of our study was to evaluate the contribution of the SPECT/CT over traditional planar imaging of patients with differentiated thyroid carcinoma (DTC).MethodsPost-therapy iodine 131 (¹³¹I) whole-body scan followed by cervico-thoracic SPECT/CT, were performed in 100 patients with DTC.ResultsAmong these 100 patients followed for a predominantly papillary DTC, planar imaging and SPECT/CT, were perfectly concordant in 70% of patients and discordant in the remaining 30%. The use of fusion imaging SPECT/CT compared to conventional planar imaging allowed us to correct our therapeutic approach in 27% (27/100 patients), according to the protocols of therapeutic management of our institute.ConclusionSPECT/CT is a hybrid imaging modality which provides better identification and more correct anatomic localization of the foci of radioiodine uptake with impact on therapeutic management.     

Recombinant Human Thyroid-Stimulating Hormone To Stimulate 131-1 Uptake For Remnant Ablation And Adjuvant Therapy

ObjectiveTo review the current literature with regard to the use of recombinant human thyroid stimulating hormone (rhTSH) as an adjunct to radioactive iodine (RAI) remnant ablation and adjuvant therapy.MethodsLiterature review of clinical studies examining rhTSH and/or thyroid hormone withdrawal preparations for RAI remnant ablation. The primary endpoints evaluated were (1) effectiveness at ablating the thyroid bed as demonstrated by the lack of significant uptake in the thyroid bed on follow-up diagnostic imaging and (2) effectiveness in facilitating the adjuvant therapy function of RAI ablation as manifested by follow-up thyroid stimulating hormone (TSH)-stimulated serum thyroglobulin levels and clinical outcomes (recurrence rates, likelihood of having no evidence of disease at final follow-up).ResultsRAI remnant ablation can be successfully achieved using either traditional thyroid hormone withdrawal or recombinant human TSH preparation. While initial studies included primarily thyroid cancer patients at low risk of recurrence, more recent studies suggest that rhTSH can also be effectively used as preparation for RAI ablation in patients with an intermediate or high risk of recurrence. Furthermore, while early studies focused primarily on the endpoint of thyroid bed remnant ablation, more recent retrospective studies suggest that final clinical outcomes (recurrence rates, likelihood of achieving no evidence of disease status at final follow-up) over 5-10 years of follow-up are very similar with either method of preparation.ConclusionrhTSH is an effective alternative to thyroid hormone withdrawal in preparation for RAI remnant ablation in patients without evidence of distant metastases who are at low, intermediate, or high risk of recurrence.     

Radioiodine Remnant Ablation: Current Indications and Dosing Regimens

ObjectiveTo review and comment on current indica tions for radioiodine remnant ablation (RRA) in patients with differentiated thyroid cancer.MethodsThe stratification of patients as potential candidates for RRA, the benefits and risks of RRA, and the optimal preparation and administered doses of iodine 131 for RRA are discussed.ResultsWhen RRA for patients with low and inter mediate-risk differentiated thyroid cancer is being consid ered, the benefits—including survival, influence on mor bidity and recurrence, and ease of monitoring—should be weighed against the potential risks. RRA should have limited use in many low-risk patients, particularly those with stage I disease who are young and have small pri mary tumors, no lymph node involvement, and no extrano dal invasion. Measurement of serum thyroglobulin 6 to 8 weeks after thyroidectomy during levothyroxine suppres sion can be used for further stratification of risk in these patients. RRA should be used only selectively in low to intermediate-risk patients and reserved primarily for older patients with large tumors, extensive lymph node involve ment, and high-risk (tall cell, insular) subtypes of differ entiated thyroid cancer. Most low-risk to intermediate-risk patients who do warrant RRA can be prepared with recom binant human thyroid-stimulating hormone and given the smallest dose possible (30 to 50 mCi of iodine 131) for successful remnant ablation. Single-photon emission com puted tomography-computed tomographic imaging and dosimetry are new tools that can help in the management of many patients with thyroid cancer.ConclusionAlthough a large database study has shown a trend of increased use of RRA after thyroidectomy between 1990 and 2008 in the United States, recent studies and guidelines suggest a more limited use in patients with low-risk disease, which may change this trend. (Endocr Pract. 2012;18:604-610)     

Recurrent Differentiated Thyroid Cancer

ObjectiveTo discuss the risk of recurrence in patients with differentiated thyroid cancer and emphasize the importance of risk-group stratification.MethodsCommon risk factors associated with recur rent thyroid cancer are outlined, and appropriate manage ment strategies are reviewed.ResultsThe overall prognosis in patients with dif ferentiated thyroid cancer is excellent. Factors associated with recurrent thyroid cancer include extrathyroidal exten sion of the primary tumor, bulky nodal metastatic lesions, macroscopic local invasion, and aggressive histologic subtypes. The locoregional recurrence and mortality are higher in patients with high-risk thyroid cancers. Patients initially presenting with locally aggressive and advanced thyroid cancer have a higher incidence of recurrent disease in the thyroid bed or nodal metastasis. These patients also have a high incidence of distant metastatic lesions. Locally recurrent thyroid cancer may be seen in more than 25% of patients with aggressive differentiated thyroid cancer. Recurrent disease in the thyroid bed can be a difficult prob lem to manage because of the proximity of the tumor to the recurrent laryngeal nerve, visceral structures in the central compartment, and occasional involvement of the trachea or larynx. External beam radiation therapy after surgical treatment may be important for better local control in the thyroid bed region, especially in patients with poorly dif ferentiated histologic features. The role of additional radio iodine therapy remains undefined at this stage.ConclusionManagement of patients with recur rent thyroid cancer necessitates a true multidisciplinary approach. These patients require close follow-up, with cross-sectional imaging and positron emission tomo graphic scanning in selected individuals. (Endocr Pract. 2012;18:600-603)     

Practical Barriers to Implementation of Thyroid Cancer Guidelines in the Asia-Pacific Region

Objective: Numerous published guidelines have described the optimal management of thyroid cancer. However, these rely on the clinical availability of diagnostic and therapeutic modalities. We hypothesized that the availability of medical resources and economic circumstances vary in Asia-Pacific countries, making it difficult to implement guideline recommendations into clinical practice.Methods: We surveyed participants at the 2009 and 2013 Congresses of the Association of Southeast Asian Nations Federation of Endocrine Societies by distributing questionnaires to attendees at registration.Results: Responses were obtained from 268 respondents in 2009 and 163 respondents in 2013. Similar to the high prevalence of low-risk thyroid cancer observed in the Surveillance, Epidemiology, and End Results database, across the Asia-Pacific countries surveyed in 2009 and 2013, 50 to 100% of the respondents from the Philippines, Malaysia, Singapore, China, Taiwan, Thailand, Hong Kong, Korea, and Sri Lanka reported that more than 50% of the patients had low-risk thyroid cancer on follow-up. Importantly, there was much variation with regards to the perceived availability of investigation and treatment modalities.Conclusion: We found a wide variation in clinicians' perception of availability of diagnostic and therapeutic modalities in the face of a rise in thyroid cancer incidence and thyroid cancer management guidelines that emphasized their importance. The lack of availability of management tools and treatments will prove to be a major barrier to the implementation of thyroid cancer management guidelines in Southeast Asia, and likely in other parts of the world as well.Abbreviations: AFES = ASEAN Federation of Endocrine Societies ASEAN = Association of Southeast Asian Nations ATA = American Thyroid Association FNA = fine-needle aspiration PET = positron emission tomography RAI = radioactive iodine Tg = thyroglobulin TSH = thyroid-stimulating hormone     

The Role of F-Fluorodeoxyglucose (FDG) Positron Emission Tomography–Computed Tomography (PET/CT) in the Screening of Cervical Cancer: A Literature Review

F-fluorodeoxyglucose (FDG) positron emission tomography–computed tomography (PET/CT) has of late gained prominence in the investigation of cervical cancer since it gives a better clarity on imaging modalities for the status of the lymph node and distant metastasis. The current review is an appraisal of the recent updates on the role of FDG-PET/CT in the screening of cervical cancer as evidenced by publications till date. 985 studies were obtained in the initial search on cervical cancer and publications selected based on inclusion and exclusion criteria. In the final selection, 14 were selected and coded as the most appropriate for the present review. Valuable studies on (FDG) PET/CT have been identified. These studies point to the fact that recent advanced protocols like PET/CT supported by therapeutic innovations ensure better cancer care and survival chances in cervical cancer patients.     

Management of Low-Risk Differentiated Thyroid Cancer

ObjectiveTo summarize the definitions of and management recommendations for low-risk thyroid cancer made by the American and European Thyroid Associations and synthesize this information with the recent literature, including systematic evaluations of tumor staging systems guiding therapy.MethodsThe American Thyroid Association and European Thyroid Association guidelines were compared and pertinent literature since 2005 was reviewed.ResultsOf papillary thyroid microcarcinomas (PTMC), up to 50% breach the thyroid capsule, 64% have lymph node metastases, up to 43% are multifocal, and as many as 2.8% have distant metastases. Locoregional and distant recurrences are, respectively, as high as 5.9% and 1.5%. As many as 1 in 4 patients with a papillary thyroid carcinoma 1.5 cm or smaller develop persistent disease. Cancer-related mortality rates are usually less than 1%, but are as high as 2% in some reports. Tumor staging systems are too inaccurate to guide therapy.ConclusionIt is unlikely that many patients will forgo treatment after understanding their risk, especially when total thyroidectomy and radioiodine (¹³¹I) therapy can reduce the PTMC recurrence or persistence disease rate to zero. Preoperatively diagnosed PTMC should be treated with total or near-total thyroidectomy, regardless of tumor size. For very low-risk patients with unifocal PTMC smaller than 1 cm that is removed by chance during surgery to treat benign thyroid disease, lobectomy alone without ¹³¹I therapy may be sufficient therapy if there are no concerning histologic features and no tumor extension beyond the thyroid, metastases, history of head and neck irradiation, or positive family history—any of which requires total or near-total thyroidectomy and remnant ablation with 30 mCi. (Endocr Pract. 2007;13:498-512)     

影像学在肾癌靶向治疗中的临床应用价值-现状与展望

肾癌为最常见的肾脏恶性肿瘤,其易复发及易出现远隔转移,靶向治疗已逐渐成为肾癌治疗中不可或缺的治疗手段。由于RECIST标准评价实体瘤疗效具有明显的局限性,临床实践中常使用电子计算机断层扫描(CT)、磁共振成像(MRI)评价疗效。随着技术的不断发展,很多新颖的影像学手段如动态增强超声(DCE-US)、正电子发射断层显像(PET-CT)等可以更准确更早期地评价及预测靶向治疗的疗效。本文对肾癌靶向治疗的影像学现状及展望进行综述。     

Ultrasonographic Differentiation of Cervical Lymph Nodes in Patients with Papillary Thyroid Carcinoma After Thyroidectomy and Radioiodine Ablation: A Prospective Study

ObjectiveThe objective of the present study was to validate an ultrasound (US) classification of cervical lymph nodes (LNs) in patients with papillary thyroid cancer (PTC) after thyroidectomy and radioactive iodine (¹³¹I) ablation.MethodsWe performed a prospective study in which the patients were submitted to thyroidectomy and ¹³¹I ablation and then followed until neck US revealed LN(s) ≥ 5 mm. A total of 288 LNs from 112 patients with PTC were evaluated. Patient management was based on LN characteristics grouped according to the classification system studied here.ResultsThe presence of microcalcifications and/or cystic degeneration of cervical LNs were highly suggestive of a metastatic etiology (specificity of 99.4%). In contrast, the most sensitive finding for LNs affected by PTC was the absence of an echogenic hilum (sensitivity of 100%). In the absence of these findings (microcalcifications, cystic degeneration, echogenic hilum), a metastatic etiology was the most likely in the case of a round LN (specificity of 89%). The differentiation of a spindle-shaped LN without a visible hilum by Doppler analysis permitted us to dichotomize an initial probability of metastases of 13% in 25% (with peripheral vascularization) versus 3.3% (without peripheral vascularization).ConclusionsOur results confirm that the classification proposed for cervical LNs in patients with PTC is valid for determining patient management following initial therapy. (Endocr Pract. 2014;20:293-298)     

Updated Review of Nuclear Molecular Imaging of Thyroid Cancers

ObjectivesWe initiate this comprehensive review to update the advances in this field by objectively elucidating the efficacies of promising radiopharmaceuticals.MethodsWe performed a comprehensive PUBMED search using the combined terms of “thyroid cancer” and “radiopharmaceuticals” or “nuclear medicine”, yielding 3273 and 11026 articles prior to December 31, 2020, respectively.ResultsBased on the mechanism of molecular metabolism, the evaluation of differentiated thyroid cancer and dedifferentiated thyroid cancer is largely centered around radioiodine and fluorine 18 (¹⁸F)-fludeoxyglucose, respectively. Further, ¹⁸F-L-dihydroxyphenylalanine and gallium 68 DOTATATE are the preferred tracers for medullary thyroid cancer. In dedifferentiated medullary thyroid cancer and anaplastic thyroid cancer, ¹⁸F-fludeoxyglucose is superior.ConclusionsThe future lies in advances in molecular biology, novel radiopharmaceuticals and imaging devices, paving ways to the development of personalized medication for thyroid cancer patients.     

Implementing Key Changes in The American Thyroid Association 2015 Thyroid Nodules/Differentiated Thyroid Cancer Guidelines Across Practice Types

Objective: This article provides suggestions to help clinicians implement important changes in the 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma (“ATA 2015”) across diverse settings.Methods: Key ATA 2015 changes are summarized regarding: (1) thyroid nodule management; (2) lobectomy versus thyroidectomy for differentiated thyroid carcinoma (DTC); and (3) surveillance following primary treatment of DTC. Advice to facilitate implementation is based on clinical experience and selected literature.Results: Strategies are described to enhance acquisition of high-quality information that helps identify patients who may possibly avoid fine-needle aspiration (FNA) of thyroid nodules or total thyroidectomy for DTC, or undergo less intense postoperative surveillance. Sonographic imaging of nodules may improve if sonograms are obtained by clinicians ordering or performing FNA or trusted high-volume sonographers. Cytopathologic assessment and reporting can be improved by working with regional or national experts. Pre-operative evaluation by endocrinologists is important so that patients are referred to experienced, proficient surgeons and assisted with well-informed decision-making regarding surgical radicality. Endocrinologists and surgeons should ensure performance of pre-operative neck ultrasonography, voice/laryngeal evaluation, and contrast-enhanced cross-sectional imaging when appropriate. Findings should be disseminated to all healthcare team members, ideally through a comprehensive medical record accessible to the entire team.Conclusion: Optimization of the sequence of specialist visits and assembly of interactive multidisciplinary teams coupled with intensified interdisciplinary and patient communication may enable clinicians to more effectively implement ATA 2015, which calls for more individualized, and often, less “invasive” management of thyroid nodules and DTC.Abbreviations: ATA 2009 = 2009 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma; ATA 2015 = 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Carcinoma; DTC = differentiated thyroid carcinoma; FNA = fine-needle aspiration; PET/CT = positron emission tomography/computed tomography     

Unusual spread of the follicular thyroid carcinoma,metastases to liver and pancreas

We report a multimetastatic follicular thyroid carcinoma(FTC) with match lesions between ¹⁸F-FDG PET/CT and post-treatment ¹³¹I imaging. The patient had a history of thoracic vertebra corpectomy surgery and liver tru-cut biopsy; both resulted in metastases of FTC. After total thyroidectomy surgery, the patient was referred to the ¹⁸F-FDG PET/CT to investigate other possible metastatic foci. ¹⁸F-FDG PET/CT showed increased FDG uptakes on a cervical lymph node, bones, lung, liver, and pancreas. After treatment of ¹³¹I, post-treatment iodine scintigraphy demonstrated iodine uptakes in the same areas as the ¹⁸F-FDG PET/CT scan and at the thyroid bed. All the matched lesions were concluded as a spread of the FTC. Here we describe an infrequent differentiated thyroid carcinoma case with metastases to the liver and pancreas. This case report also highlights the importance of ¹⁸F-FDG PET/CT in determining the extent of thyroid cancer.     

Positron emission tomography (18FDG-PET) in the detection of medullary thyroid carcinoma metastases

INTRODUCTION: Medullary thyroid carcinoma (MTC) is usually more advanced at presentation than differentiated thyroid cancers and often has distant metastases. The primary treatment of MTC is total thyroidectomy and regional lymph node dissection. The efficacy of these procedures has been limited by the aggressiveness of the disease and metastatic spread at the time of surgery. Persistently elevated levels of calcitonin (CT) and carcinoembryonic antigen (CEA) or their increase postoperatively are indicative for residual or recurrent disease. Conventional imaging methods such as ultrasonography, computed tomography, magnetic resonance imaging and MIBI scintigraphy usually fail to find the source of calcitonin. Better imaging properties have been shown by DMSA scintigraphy, somatostatin receptor scintigraphy or by positron emission tomography (PET). The aim of the study was to evaluate the diagnostic accuracy of PET for the localisation of occult MTC in patients after surgery with increased concentrations of CT, in whom conventional imaging procedures have not been successful. MATERIAL AND METHODS: The PET investigation using (18)F-fluoro- 2-deoxy-D-glucose combined with computed tomography ((18)FDG-PET/CT) was performed at the Department of Nuclear Medicine (Oncology Centre in Bydgoszcz) between January and October 2004. In five patients with postoperative calcitonin ranging from 164 to > 2000 ng/l (normal < 10 ng/l) no tumour lesions were found using other imaging methods. RESULTS: In four of five cases, responsible lesions with a higher metabolism of FDG, indicating MTC tissue (remnants or metastases), were localised. In one patient no focus of FDG accumulation was found despite high CT concentration. PET detected tumour manifestations in the neck and the mediastinum in two patients, in the lung and the left adrenal gland in one case and in the neck and the liver in another patient. As a result of surgery for the removal of a residual tumour or metastases the accuracy of diagnosis was confirmed by histopathology in all four cases and a decrease in CT and CEA levels was observed in 3/4 cases. The metabolic imaging findings by PET/CT ensured that the surgery on these patients was successful. CONCLUSIONS: For the detection of occult residual or metastatic MTC lesions, (18)FDG-PET is a valuable procedure in imaging diagnostics.     

Immunoglobulin Preparations Can Mislead Clinical Decision-Making in Follow-Up of Differentiated Thyroid Cancer

Objective: Intravenous and subcutaneous immunoglobulins are commonly used for immune substitution or as immune modulators in a variety of inflammatory and autoimmune disorders. Exogenous thyroid-specific thyroglobulin (Tg) antibodies present in the donor plasma may interfere with the interpretation of measurements of Tg autoantibodies (Tg-Abs) in the recipient’s plasma and potentially trigger an immune response in the recipient’s immune cells. Levels of antibodies causing bioassay interferences or those leading to clinically relevant changes in patient outcomes are not known. Tg is used as a biomarker in the long-term surveillance of patients with differentiated thyroid cancer (DTC) following total thyroidectomy and radioactive iodine ablation. However, the presence of Tg-Abs in the circulation interferes with Tg measurements. Assessment of levels of Tg-Abs is thus recommended as a part of standard follow-up of DTC together with Tg testing.Methods: To understand the potential mechanisms and pathophysiologic significance of possible interferences associated with administration immunoglobulin preparations and Tg measurement, we overview the current knowledge on interactions between Tg autoimmunity and immunoglobulin preparations and illustrate diagnostic challenges and perspectives for follow-up of patients with DTC treated with exogenous immunoglobulins.Results: In patients with DTC treated with immunoglobulin preparations, monitoring of thyroid cancer using Tg and Tg-Abs is challenging due to possible analytical interferences through passive transfer of exogenous antibodies from immunoglobulin preparations.Conclusion: Analytical interferences must be suspected when a discrepancy exists between clinical examination and diagnostic tests. Collaboration between endocrinologists, biologists, and pharmacologists is fundamental to avoid misdiagnosis and unnecessary medical or radiologic procedures.Abbreviations: CT = computed tomography; DTC = differentiated thyroid cancer; FNAB = fine-needle aspiration biopsy; HAb = heterophile antibody; IMA = immunometric assay; IVIg = intravenous immunoglobulin; RAI = radioactive iodine; RIA = radioimmunoassay; SCIg = subcutaneous immunoglobulin; Tg = thyroglobulin; Tg-Ab = thyroglobulin autoantibody; Tg-MS = thyroglobulin mass spectrometry; TPO-Ab = thyroid peroxidase autoantibody; TSHR-Ab = thyrotropin receptor autoantibody