Glycemic Trends in Patients with Thyroid Eye Disease Treated with Teprotumumab in 3 Clinical Trials.

PURPOSE: Assess incidence, severity, and glucose excursion outcomes in thyroid eye disease (TED) patients receiving the insulin-like growth factor-1 receptor inhibitor teprotumumab from 3 clinical trials. DESIGN: Analysis of pooled glycemic data over time. PARTICIPANTS: Eighty-four teprotumumab- and 86 placebo-treated active TED patients from the phase 2 and phase 3 (OPTIC) controlled clinical trials and 51 teprotumumab-treated patients from the OPTIC extension (OPTIC-X) trial. METHODS: Eight intravenous infusions were given over 21 weeks. Phase 2 serum glucose was measured at weeks 1, 4, 15, and 21, with fasting measurements at weeks 1 and 4. Serum glucose was measured at each study visit in OPTIC and OPTIC-X, with fasting measurements at weeks 1 and 4 (in patients without diabetes) or all visits (in patients with diabetes). In all studies, hemoglobin A1c (HbA1c) was measured at baseline, 12, and 24 weeks plus weeks 36 and 48 in OPTIC-X. MAIN OUTCOME MEASURES: Serum glucose and HbA1c. RESULTS: In the phase 2 and 3 studies, 9 hyperglycemic episodes occurred in 8 teprotumumab patients; mean HbA1c level increased 0.22% from baseline to week 24 (to 5.8%; range, 5.0%-7.9%) versus 0.04% in patients receiving the placebo (to 5.6%; range, 4.6%-8.1%). At study end, 78% (59/76) of teprotumumab patients and 87% (67/77) of patients receiving placebo had normoglycemic findings. Normoglycemia was maintained in 84% (57/68) of patients receiving teprotumumab and 93% (64/69) of patients receiving placebo. Among baseline prediabetic patients, 43% (3/7) remained prediabetic in both groups, and 29% (2/7) of teprotumumab patients and 14% (1/7) of patients receiving placebo had diabetic findings at week 24. OPTIC-X patients trended toward increased fasting glucose and HbA1c whether initially treated or retreated with teprotumumab. Fasting glucose commonly rose after 2 or 3 infusions and stabilized thereafter. Most hyperglycemic incidents occurred in patients with baseline prediabetes/diabetes but were controlled with medication. No evidence was found for progression or increased incidence of hyperglycemia with subsequent doses. CONCLUSIONS: Serious glycemic excursions are uncommon in patients with normoglycemia before teprotumumab therapy. Patients with controlled diabetes or impaired glucose tolerance can be treated safely if baseline screening, regular monitoring of glycemic control, and timely treatment of hyperglycemia are practiced. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Future Projections in Thyroid Eye Disease.

BACKGROUND AND AIMS: This review aims to summarize current and emerging therapies for treatment of thyroid eye disease (TED), in the light of novel understanding of pathogenetic mechanisms, leading to new treatment options and clinical trials. METHODS: We reviewed and analyzed peer-reviewed literature reporting recent translational studies and clinical trials in the treatment of TED. Searches were made at www.pubmed.gov with keywords "thyroid eye disease," "Graves' ophthalmopathy," "thyroid orbitopathy," and "Graves' orbitopathy." RESULTS: Surgery is reserved for rehabilitation in chronic TED or for emergent compressive optic neuropathy. Oral and intravenous glucocorticoid therapy has been used for decades with variable efficacy in acute TED, but results may be temporary and side effects significant. Nonsteroidal oral immunosuppressive agents offer modest benefit in TED. Several immunomodulatory monoclonal antibodies, including rituximab and tocilizumab, have shown efficacy for inactivating TED. Recently, teprotumumab, an insulin-like growth factor 1 receptor (IGF-1R) inhibitor, has demonstrated significant improvement in proptosis, clinical activity score, diplopia, and quality of life in patients with active TED, with good tolerability. Newly proposed TED therapies, currently in preclinical and clinical trial phases, include thyroid-stimulating hormone (TSH) receptor inhibitory drugs, RVT-1401, local anti-vascular endothelial growth factor therapy, IGF-1R drugs delivered subcutaneously and orally, and desensitization to the TSH receptor with modified TSH receptor peptides. CONCLUSION: New, albeit incomplete, understanding of the molecular mechanisms of TED has led to new promising therapies and offered improved outcomes in TED patients. Their full role and their relationship to classical immune suppression should be clarified over the next few years.

Thyroglobulin Assay Interferences: Clinical Usefulness of Mass-Spectrometry Methods.

Context: Thyroglobulin autoantibodies (TgAbs) affect thyroglobulin immunometric assays (TgIMAs), causing falsely low results. Conversely, heterophilic antibodies (HAs) may cause falsely elevated results. Thyroglobulin (Tg) measurements by mass spectrometry (MS) resist antibody interference. The most effective use of TgIMA/TgMS in the evaluation of Tg remains unclear. Objective: The objective of this work was to study the usefulness of TgMS vs TgIMA in the presence of Tg measurement interference by HA and TgAb. Methods: In 163 thyroid cancer patients, Tg was postoperatively measured by TgIMA and TgMS. When TgIMA was elevated and TgMS undetectable, HA was assessed by serial dilution and pretreatment with HA blocking reagent. TgIMA and TgMS were compared in TgAb-positive patients with well-characterized clinical status. Results: 6 out of 45 cases with TgIMA >1 ng/mL had undetectable TgMS. HA interference was confirmed by serial dilution and HA blocking reagent addition. In TgAb-positive cases, TgIMA and TgMS were highly correlated (R2 = 0.86). In patients with structural disease and TgAb, TgIMA and TgMS were detectable in 6/19 patients, and 9/19 cases, respectively. The TgMS concentration range in the 3 discrepant cases ranged from 0.5 to 2.0 ng/mL. Hence, the presence of TgAb was associated with inappropriately reduced Tg concentrations with both TgIMA and TgMS. Conclusion: HA cause falsely elevated TgIMA with undetectable TgMS with significant frequency. TgMS can be used to rule out HA interference. Albeit resistant to TgAb in vitro, TgMS detects little Tg in patients with TgAb and structural disease. Hence, TgAb may reduce Tg concentrations in vivo. The implication is that no assay design may be able to overcome this problem. TgMS may not detect structural disease in TgAb-positive patients.

Proptosis and Diplopia Response With Teprotumumab and Placebo vs the Recommended Treatment Regimen With Intravenous Methylprednisolone in Moderate to Severe Thyroid Eye Disease: A Meta-analysis and Matching-Adjusted Indirect Comparison.

IMPORTANCE: Thyroid eye disease can be a debilitating autoimmune disorder characterized by progressive proptosis or diplopia. Teprotumumab has been compared with placebo in randomized clinical trials, but not with intravenous methylprednisolone (IVMP), which sometimes is used in clinical practice for this condition. OBJECTIVE: To conduct a matching-adjusted indirect comparison of teprotumumab vs IVMP vs placebo. DATA SOURCES: Deidentified patient-level data from teprotumumab trials and aggregate-level data from literature on the most recommended regimen of IVMP. STUDY SELECTION: PubMed and Embase were searched for randomized/observational studies using key terms and controlled vocabulary. Full texts of eligible articles were reviewed and cataloged. DATA EXTRACTION AND SYNTHESIS: Conducted by 1 reviewer (R.A.Q.) and 1 verifier (R.B.), including study characteristics, eligibility criteria, baseline characteristics, and outcomes. MAIN OUTCOMES AND MEASURES: Changes in proptosis by millimeter and diplopia response (percentage with ≥1 grade reduction) from baseline to week 12 in patients receiving IVMP and placebo, and to week 24 in patients receiving teprotumumab. RESULTS: The search identified 1019 records, and 6 through manual searches, alerts, and secondary references. After excluding duplicates and screening full-text records, 12 IVMP studies were included in the matching-adjusted indirect comparison (11 for proptosis change [n = 419], 4 for diplopia response [n = 125], and 2 teprotumumab [n = 79] and placebo [n = 83] comparator studies). Treatment with IVMP resulted in a proptosis difference of -0.16 mm (95% CI, -1.55 to 1.22 mm) from baseline to week 12 vs placebo. The proptosis treatment difference between IVMP and teprotumumab of -2.31 mm (95% CI, -3.45 to -1.17 mm) favored teprotumumab. Treatment with IVMP (odds ratio, 2.69; 95% CI, 0.94-7.70) was not favored over placebo in odds of diplopia response; however, teprotumumab was favored over IVMP (odds ratio, 2.32; 95% CI, 1.07-5.03). CONCLUSIONS AND RELEVANCE: This meta-analysis suggests that use of IVMP is associated with a small, typically not clinically relevant, change from baseline in proptosis vs placebo, with modest changes in diplopia. While this nonrandomized comparison suggests that use of teprotumumab, compared with IVMP, is associated with greater improvements in proptosis and may be twice as likely to have a 1 grade or higher reduction in diplopia, randomized trials comparing these 2 treatments would be warranted to determine if 1 treatment is superior to the other to a clinically relevant degree.

Painful Subacute Thyroiditis is Commonly Misdiagnosed as Suspicious Thyroid Nodular Disease.

OBJECTIVE: To investigate and characterize the clinical and radiologic features of 10 patients with painful subacute thyroiditis with ultrasound findings considered suspicious for malignancy or for whom biopsy of a suspicious area was recommended by an attending radiologist. PATIENTS AND METHODS: Ten patients with painful subacute thyroiditis were seen from June 1, 2016, through January 1, 2019. All 10 patients presented to an endocrine or thyroid clinic with a neck ultrasound report stating findings suspicious for malignancy or nodular disease. Clinical, laboratory, radiographic, and pathologic data were (retrospectively collected and) reviewed. RESULTS: The mean ± SD patient age was 49.0±15.0 years at diagnosis; 8 patients were female. All the patients presented with a low or undetectable serum thyrotropin level. Six of 7 patients with available inflammatory markers had elevated levels. Thyrotropin receptor antibodies were absent in all 6 patients tested. On follow-up imaging, 8 patients had complete resolution or improvement of described findings, 1 was lost to follow-up, and 1 had an incidental nodule that was biopsied after the episode of thyroiditis and found to be papillary thyroid carcinoma. CONCLUSION: Painful subacute thyroiditis demonstrates specific sonographic patterns that may be misdiagnosed as suspicious thyroid nodular disease. Recognition of the innocent and transient nature of these findings is important for the proper management and monitoring of these patients.

False Positives in Thyroglobulin Determinations Due to the Presence of Heterophile Antibodies: An Underrecognized and Consequential Clinical Problem.

OBJECTIVE: To report a case series of thyroid cancer patients in whom false positive results in immunometric assays for thyroglobulin (TgIMA) were caused by heterophilic antibody interference, describe the clinical scenario in which this interference should be suspected, and recommend methods to demonstrate the interference. METHODS: Three patients with unexpectedly elevated thyroglobulin results (range, 1.6-75 ng/mL) were studied. In the first patient, thyroglobulin was elevated despite the presence of Tg antibody. In the second patient, suppressed thyroglobulin was higher than a recent stimulated thyroglobulin. In the third patient, thyroglobulin became detectable years after treatment and did not change after thyroid-stimulating hormone stimulation. TgIMA concentration determination was compared to determination by a mass spectrometry method (TgMS). Thyroglobulin was also remeasured after preabsorption with heterophile antibody blocking reagents and after serial dilutions. RESULTS: In all cases, thyroglobulin was undetectable by TgMS. In 2 of 3 patients, dilutions provided nonlinear thyroglobulin results. After blocking agent preabsorption, thyroglobulin dropped by 35%, 45%, and 91% in the 3 samples. CONCLUSION: False positive thyroglobulin concentrations from heterophilic antibody interference have significant impact on the management of thyroid cancer. Here we show that TgMS assays can be used to rule out heterophilic antibody interference. This interference should be suspected when a detectable thyroglobulin by TgIMA does not respond to thyroid-stimulating hormone or is discordant from the clinical assessment.

Imaging "Thyroiditis": A Primer for Radiologists.

A variety of inflammatory disorders, generically classified as "thyroiditis," can affect the thyroid gland diffusely, generating distinctive radiographic patterns. While a precise diagnosis can seldom be made based on sonographic appearance alone, interpreting these patterns in the correct clinical and biochemical context will help support the most appropriate diagnosis. We believe that the generic term "thyroiditis" is often not helpful and often may be incorrect. Therefore, it is important for radiologists to understand the sonographic and functional correlations to provide the most appropriate differential diagnosis in their reports. This brief review is designed to provide information and guidance for radiologists when dealing with various thyroid disorders which cause diffuse changes in the thyroid and underline the pitfalls most often encountered in clinical practice.

Graves' disease.

Graves' disease (GD) is an autoimmune disease that primarily affects the thyroid gland. It is the most common cause of hyperthyroidism and occurs at all ages but especially in women of reproductive age. Graves' hyperthyroidism is caused by autoantibodies to the thyroid-stimulating hormone receptor (TSHR) that act as agonists and induce excessive thyroid hormone secretion, releasing the thyroid gland from pituitary control. TSHR autoantibodies also underlie Graves' orbitopathy (GO) and pretibial myxoedema. Additionally, the pathophysiology of GO (and likely pretibial myxoedema) involves the synergism of insulin-like growth factor 1 receptor (IGF1R) with TSHR autoantibodies, causing retro-orbital tissue expansion and inflammation. Although the aetiology of GD remains unknown, evidence indicates a strong genetic component combined with random potential environmental insults in an immunologically susceptible individual. The treatment of GD has not changed substantially for many years and remains a choice between antithyroid drugs, radioiodine or surgery. However, antithyroid drug use can cause drug-induced embryopathy in pregnancy, radioiodine therapy can exacerbate GO and surgery can result in hypoparathyroidism or laryngeal nerve damage. Therefore, future studies should focus on improved drug management, and a number of important advances are on the horizon.

Thyroid Function Changes in the Elderly and Their Relationship to Cardiovascular Health: A Mini-Review.

BACKGROUND: Thyroid hormones have significant effects on the cardiovascular systems. In general, hyperthyroidism is associated with an increased risk of dysrhythmias, while hypothyroidism may cause atherosclerosis. Recent large studies have sought to identify aging-associated changes in thyroid function and their relevance to cardiovascular morbidity and mortality in the elderly. Conflicting results have often been published, likely due to the heterogeneity of the studied populations. OBJECTIVE: This review seeks to briefly summarize the most recent large population studies analyzing thyroid changes with aging and interpreting their effects on cardiovascular health in the elderly. METHODS: Selective review of recent literature. RESULTS: The emerging pattern suggests a slight decrease in thyroid function in the elderly leading to slightly higher thyroid stimulating hormone (TSH) levels. However, the incidence of mild hyperthyroidism also increases, especially in populations with historical or current iodine deficiency. Large observational studies suggest that the potential harm from mild hypothyroidism seen in younger population tends to diminish in older subjects, while the harm from mild hyperthyroidism becomes more significant. A markedly increased risk of atrial fibrillation is a well-established consequence of subclinical hyperthyroidism in patients in the sixth decade of life and beyond. CONCLUSIONS: The absence of large prospective interventional data does not allow the formulation of strict clinical recommendations, but a higher TSH threshold for treating both subclinical hypothyroidism and subclinical hyperthyroidism in the elderly seems reasonable.

Reassessing risks and benefits of living kidney donors with a history of thyroid cancer.

Many potential and willing living kidney donors are excluded from donating for a history of malignancy. There is appropriate caution toward patients with a history of malignancy because of concern for transmission of donor-derived malignancy. Thyroid cancer is common and increasing in incidence, and outcomes are very good in otherwise young, healthy potential donors. We review the evidence and guidelines regarding recurrence and transmission risk of thyroid cancer, and then we suggest a standardized guideline for otherwise healthy donors with a history of thyroid malignancy.

Misdiagnosis of Graves' Disease with Apparent Severe Hyperthyroidism in a Patient Taking Biotin Megadoses.

BACKGROUND: Accurate immunoassays measuring minute quantities of hormones are the cornerstone of the practice of endocrinology. Despite tremendous advances in this field, novel pitfalls in these tests emerge from time to time. Oral biotin can interfere with immunoassays of several hormones. The purpose of this report is to relate an extreme case of such interference. PATIENT FINDINGS: A patient with progressive multiple sclerosis was found to have extremely elevated free thyroxine, triiodothyronine, and suppressed thyrotropin (TSH) levels. His TSH receptor binding inhibiting antibody level was also elevated. This constellation of laboratory findings suggested a diagnosis of severe Graves' disease. All of the assays yielding abnormal results employed the biotin-streptavidin affinity in their design. The patient had no symptoms of hyperthyroidism, and detailed review of his medications revealed intake of megadoses of biotin. Temporary discontinuation of biotin treatment resulted in complete resolution of the biochemical abnormalities. CONCLUSIONS: Non-physiologic biotin supplementation may interfere with several immunoassays, including thyroid hormones, TSH, thyroglobulin, and TSH receptor binding inhibiting antibody, leading to erroneous diagnoses. Questioning for biotin intake should be part of the evaluation for patients undergoing endocrine tests. Interruption of biotin supplementation for at least two days prior to biotin-sensitive tests should be sufficient to avoid major misdiagnoses.

Cross-cultural validity of the thyroid-specific quality-of-life patient-reported outcome measure, ThyPRO.

BACKGROUND AND PURPOSE: Thyroid diseases are common and often affect quality of life (QoL). No cross-culturally validated patient-reported outcome measuring thyroid-related QoL is available. The purpose of the present study was to test the cross-cultural validity of the newly developed thyroid-related patient-reported outcome ThyPRO, using tests for differential item functioning (DIF) according to language version. METHODS: The ThyPRO consists of 85 items summarized in 13 multi-item scales and one single item. Scales cover physical and mental symptoms, well-being and function as well as social and daily function and cosmetic concerns. Translation applied standard forward-backward methodology with subsequent cognitive interviews and reviews. Responses (N = 1,810) to the ThyPRO were collected in seven countries: UK (n = 166), The Netherlands (n = 147), Serbia (n = 150), Italy (n = 110), India (n = 148), Denmark (n = 902) and Sweden (n = 187). Translated versions were compared pairwise to the English version by examining uniform and nonuniform DIF, i.e., whether patients from different countries respond differently to a particular item, although they have identical level of the concept measured by the item. Analyses were controlled for thyroid diagnosis. DIF was investigated by ordinal logistic regression, testing for both statistical significance and magnitude (ΔR (2) > 0.02). Scale level was estimated by the sum score, after purification. RESULTS: For twelve of the 84 tested items, DIF was identified in more than one language. Eight of these were small, but four were indicative of possible low translatability. Twenty-one instances of DIF in single languages were identified, indicating potential problems with the particular translation. However, only seven were of a magnitude which could affect scale scores, most of which could be explained by sample differences not controlled for. CONCLUSION: The ThyPRO has good cross-cultural validity with only minor cross-cultural invariance and is recommended for use in international multicenter studies.

Clinical review: Clinical utility of TSH receptor antibodies.

CONTEXT: TSH receptor antibodies (TRAb) cause Graves' disease (GD) hyperthyroidism. Widely available TRAb measurement methods have been significantly improved recently. However, the role of TRAb measurement in the differential diagnosis of hyperthyroidism, the prediction of remission of GD hyperthyroidism, the prediction of fetal/neonatal thyrotoxicosis, and the clinical assessment of Graves' ophthalmopathy (GO) are controversial. EVIDENCE ACQUISITION: We reviewed and analyzed the literature reporting primary data on the clinical use of TRAb. We focused our analyses on clinical studies analyzing third-generation TRAb assays. EVIDENCE SYNTHESIS: The performance of TRAb in the differential diagnosis of overt hyperthyroidism is excellent, with sensitivity and specificity in the upper 90%. TRAb can accurately predict short-term relapses of hyperthyroidism after a course of antithyroid drugs but are less effective in predicting long-term relapses or remissions. Pregnancies in women with GD with negative TRAb are highly unlikely to result in fetal hyperthyroidism, whereas high titers of TRAb in pregnancy require careful fetal monitoring. GD patients with GO frequently have high TRAb levels. However, there are insufficient data to use the test to predict the clinical course of GO and response to treatment. CONCLUSIONS: Third-generation TRAb assays are suitable in the differential diagnosis of hyperthyroidism. In GD, TRAb should be tested before deciding whether methimazole can be stopped. TRAb should be used in pregnant women with GD to assess the risk of fetal thyrotoxicosis. The use of TRAb in GO requires further studies.

Management of thyroid nodules with atypical cytology on fine-needle aspiration biopsy.

BACKGROUND: Fine-needle aspiration biopsy (FNAB) of the thyroid categorized as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is a newly defined category according to the recent Bethesda guidelines. We sought to assess the characteristics and treatment of patients with an AUS/FLUS FNAB at our institution. Additionally, we evaluated the utility of the recommended 3-month timing of repeat FNAB. METHODS: A retrospective study of all patients with an FNAB categorized as AUS/FLUS at an academic tertiary-care center. Clinical, cytological, and ultrasound variables were compared among management groups. Differences in patients receiving repeat FNAB before or after a 3-month interval were compared. RESULTS: A total of 203 patients of the 5,391 FNABs performed at our institution met the Bethesda criteria for AUS/FLUS; 62% were sent directly to surgery, 25% had a repeat FNAB, and 13% were observed. Younger (p=0.006) and male patients (p=0.04) were more likely to go directly to surgery. Microcalcifications, irregular margins, and marked hypoechogenicity on ultrasound did not appear to influence the decision to repeat the FNAB, observe the patient, or refer the patient for surgery. Timing of repeat FNAB (<3 months or ≥3 months) did not alter the diagnostic results of the second FNAB (p=0.73). The overall rate of malignancy in patients undergoing surgery was 15.7%. CONCLUSIONS: Gender and age, not ultrasound characteristics, appear to influence the decision for surgery in AUS/FLUS patients. Timing of repeat biopsy did not alter management, repeat FNAB diagnosis, or rate of malignancy in our cohort.

Diagnostic yield of nondiagnostic thyroid nodules is not altered by timing of repeat biopsy.

BACKGROUND: Guidelines from the National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference recommend a repeat fine-needle aspiration biopsy (FNAB) after 3 months for thyroid nodules with a nondiagnostic (ND) result. Our aims were to assess which factors influenced their clinical management and to determine if the timing of the repeat FNAB affects the diagnostic yield. METHODS: A retrospective institutional review of 298 patients from 1/2006 to 12/2007 with an ND FNAB was performed. The factors influencing the next step in management, including age, gender, history of radiation, presence of Hashimoto's thyroiditis, thyroid-stimulating hormone levels, and ultrasound characteristics, were evaluated. The effect of the time of the repeat FNABs on their diagnostic yield was assessed. RESULTS: Of the 298 patients in our cohort, 9% were referred directly for surgery, 76% had a repeat FNAB, and 15% were observed. Tumor size was the only independent variable correlated with treatment strategy after a ND FNAB. There was not a significant difference in diagnostic yields between repeat FNABs performed earlier than 3 months compared to those preformed later (p=0.58). CONCLUSION: The timing of repeat FNAB for an initial ND FNAB does not affect diagnostic yield of the repeat FNAB.

Thyroid lobe ablation with radioactive iodine as an alternative to completion thyroidectomy after hemithyroidectomy in patients with follicular thyroid carcinoma: long-term follow-up.

BACKGROUND: Radioactive iodine lobe ablation (RAI-L-ABL) is a possible alternative to completion thyroidectomy (C-Tx) for follicular thyroid carcinoma (FTC), but no long-term outcome data are available after lobe ablation. We analyzed the long-term outcome of lobe ablation in a series of patients with FTC. METHODS: This was a retrospective study of patients who were treated with lobe ablation between 1983 and 2008. Of 134 patients with FTC, 37 (27.6%) had lobe ablation with (131)I (30-32 mCi) (RAI-L-ABL), 68 (50.7%) had C-Tx, and 29 (21.6%) had initial total thyroidectomy (T-Tx). The main outcomes analyzed were (131)I uptake after lobe ablation, C-Tx or T-Tx, serum thyroglobulin (Tg), serum thyroid-stimulating hormone (TSH), long-term disease-specific mortality, and disease-free survival. RESULTS: After lobe ablation, radioiodine uptake was significantly lower for the RAI-L-ABL group (0.6%) than for the C-Tx group (2.0%, p<0.005) or T-Tx group (1.3%, p=0.054). Subsequent remnant ablation was performed in 12 of 37 (32%) patients in the RAI-L-ABL group, in 58 of 68 (85.3%) patients in the C-Tx group, and in 25 of 29 (86.2%) patients in the T-Tx group (p<0.01). With median follow-up of 95 months for the RAI-L-ABL group, 47 months for the C-Tx group, and 53 months for the T-Tx group, there was one death in the RAI-L-ABL group and one death in the T-Tx group. No other RAI-L-ABL patients had detectable disease, whereas patients in the C-Tx group and two patients in the T-Tx group had detectable disease (p=0.18). Long-term stimulated or suppressed Tg of <1 ng/mL were found in 87.5% of the RAI-L-ABL group (n=28), 86.3% of the C-Tx group (n=57), and 77.8% of the T-Tx group (n=21). Tg was detectable in 40.6% of the RAI-L-ABL group compared to 13.8% of C-Tx and 28.6% of T-Tx groups (p<0.05, between groups). CONCLUSIONS: RAI-L-ABL, C-Tx, and T-Tx are equally effective in achieving serum TSH concentrations of >25 mIU/L and preparing patients for conventional (131)I treatment and whole body scanning with similar long-term outcomes. However, persistent measurable Tg (range 0.2-2.2 ng/mL) is more common after RAI-L-ABL.

Central hypothyroidism in a patient with pituitary autoimmunity: evidence for TSH-independent thyroid hormone synthesis.

CONTEXT: Acquired central hypothyroidism is rare, especially when isolated, and is typically associated with detectable, although biologically inactive, serum TSH. OBJECTIVE: We describe a 56-yr-old woman with profound central hypothyroidism and partial central hypoadrenalism, in the absence of other endocrine abnormalities. In contrast to most cases of central hypothyroidism, serum TSH remained undetectable for 9 months before the initiation of thyroid hormone and hydrocortisone treatment. A test for pituitary autoantibody was moderately positive. Serum free T(4), serum T(3), and neck radioiodine uptake were low but detectable. The thyroid and pituitary glands appeared morphologically normal on neck ultrasound and head magnetic resonance imaging, respectively. SETTINGS: The study was conducted in a tertiary academic medical center. CONCLUSIONS: This case illustrates the variable clinical presentation of pituitary autoimmunity. The persistence of low but detectable thyroid hormone levels and radioiodine neck uptake in the absence of TSH suggests that significant TSH-independent thyroid hormone synthesis may occur in the normal thyroid.

Thyroid-associated paragangliomas.

BACKGROUND: Paragangliomas in the region of the thyroid gland are rare tumors that can present a diagnostic challenge by mimicking follicular and c-cell derived thyroid tumors. SUMMARY: Thyroid-associated paragangliomas are likely a subset of laryngeal paragangliomas and, although quite rare, should be considered in the differential diagnosis of a hypervascular thyroid nodule. The preoperative diagnosis of thyroid-associated paragangliomas can be challenging since the cytologic and histologic features overlap with more common primary thyroid neoplasms, in particular medullary carcinoma. Differential expression of a panel of immunohistochemical markers, including neuro-specific enolase, chromogranin A, synaptophysin, keratin, and S100, can be used to distinguish thyroid-associated paragangliomas from primary thyroid tumors. Intraoperatively, thyroid-associated paragangliomas may be associated with significant intraoperative bleeding and are often densely adherent to surrounding tissues, including the recurrent laryngeal nerve. Interestingly, the aggressive local behavior of these tumors does not correspond to potential for malignancy, as there are no patients with malignant thyroid-associated paragangliomas reported in the medical literature. Therefore, these tumors may be treated with limited resection. Postoperatively, patients with paragangliomas should receive hormonal evaluation for functional disease, imaging evaluation for multicentric and metastatic disease, and genetic counseling. CONCLUSION: Thyroid-associated paragangliomas are an important part of the differential diagnosis of a hypervascular thyroid nodule, especially in a patient with a fine-needle aspiration biopsy suggestive of medullary thyroid carcinoma, but with unremarkable serum calcitonin levels. Consideration of a thyroid-associated paraganglioma also has important operative and postoperative implications for determining the extent of thyroid resection as well as follow-up testing.

Drugs affecting thyroid function.

INTRODUCTION: Over the years, several drugs used in the treatment of nonthyroidal conditions have been shown to affect thyroid function. As novel drugs are introduced, novel interactions are described. The aim of this review is to summarize clinically relevant thyroidal side effects of drugs used for nonthyroidal conditions. Special focus is given to recent developments and to drugs with the largest clinical relevance. SUMMARY: Thyrosine kinase inhibitors are novel drugs used in the treatment of several neoplasias, including thyroid cancer. Thyroidal side effects are being increasingly detected with these drugs. Some drugs in this category affect thyroid hormone metabolism and therefore only affect patients on thyroid replacement. Others affect the thyroid directly profoundly, causing primary hypothyroidism. Immune modulators used in infectious, inflammatory, and neoplastic conditions also cause hyper- and hypothyroidism, through poorly understood immune or nonimmune mechanisms. The effects of amiodarone on the thyroid have been long recognized. However, given the complexity of these effects, several areas in this field remain problematic, such as the identification of subtypes of hyperthyroidism and the best treatment strategies. Lithium also has important antithyroid effects and it is a commonly prescribed medication. Its antithyroid effects may have clinical utility in selected clinical situations. Other drugs known to affect thyroid hormone absorption, metabolism, and transport are also briefly reviewed. CONCLUSIONS: Several drugs are known to alter thyroid function as a side effect of their primary pharmacological action. Some of these effects have been recognized for decades, but novel thyroid-drug interactions are being recognized as new drugs are developed. It is important for the clinician to be familiar with thyroid-drug interactions, as enhanced surveillance may be necessary in patients undergoing therapies known to affect thyroid function.