A Rare Case of Persistent Multifocal Cribriform-Morular Thyroid Carcinoma.

Background/Objective: Cribriform-morular thyroid carcinoma (CMTC) was considered a variant of papillary thyroid carcinoma (PTC) but is a separate entity in the 2022 World Health Organization classification. CMTC has an association with familial adenomatous polyposis (FAP). Our objective is to report a case of CMTC who was subsequently diagnosed with FAP, to highlight these associated entities and implications for management. Case Report: A 15-year-old female with a history of iron-deficiency anemia and alpha-gal syndrome presented with several years of goiter and dysphagia. She also noted unintentional weight loss, abdominal pain, melena and hematochezia, and symptomatic anemia. Physical examination was significant for multiple thyroid nodules. Laboratory results revealed normal thyroid function and iron deficiency. Multiple nodules were visualized on thyroid ultrasound, and fine needle aspiration biopsy was consistent with PTC. Total thyroidectomy was performed with a revised diagnosis of multifocal CMTC, with administration of adjuvant radioactive iodine due to persistent disease. Genetic testing confirmed FAP and she was referred for upper endoscopy, colonoscopy, and an evaluation for colectomy. Discussion: There are no best practice guidelines for management of CMTC. Management of CMTC is guided by FAP status; sporadic cases can be managed with hemithyroidectomy, while FAP-associated cases are better managed with total thyroidectomy. Recurrence is usually managed with surgical resection. The decision to treat with adjuvant radioactive iodine is often extrapolated from management of classic PTC. Conclusion: Thyroid carcinoma in the setting of extensive family history of colorectal carcinoma should arouse suspicion for CMTC. Patients with CMTC should receive a referral for colonoscopy and genetic testing for FAP.

Improved sexual function after parathyroidectomy in women with primary hyperparathyroidism.

BACKGROUND: The study aimed to evaluate whether women with primary hyperparathyroidism (PHPT) experience improvement in their sexual function after parathyroidectomy. METHODS: Women with PHPT or benign thyroid nodules (controls) undergoing surgery were administered the validated Parathyroidectomy Assessment Score (PAS), Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) and Female Sexual Function Index (FSFI) pre-operatively, at 3 months and 6 months postoperatively. RESULTS: Of the 26 PHPT and 18 control patients, PHPT patients were older (53.1 vs 45.3 years, p â€‹= â€‹0.008). Post-operatively, both PHPT (pre-op 2.4 vs 3-month 3.0 vs 6-month 2.4, p â€‹= â€‹0.022) and control patients (pre-operative 2.4 vs 3-month 3.3 vs 6-month 3.6, p â€‹= â€‹0.032) reported increased desire for sexual activities. In addition, PHPT patients experienced increased arousal (pre-operative 2.7 vs 3-month 3.9 vs 6-month 3.6, p â€‹= â€‹0.047) and satisfaction (pre-operative 3.0 vs 3-month 4.8 vs 6-month 4.0, p â€‹= â€‹0.006). CONCLUSIONS: The current study indicates that women with PHPT may experience improved sexual function after parathyroidectomy.

Efficacy of Levothyroxine Sodium Soft Gelatin Capsules in Thyroidectomized Patients Taking Proton Pump Inhibitors: An Open-Label Study.

Background: Treatment with proton pump inhibitors (PPIs) and antacids affects the gastrointestinal absorption of levothyroxine sodium (LT4) tablets. Patients with hypothyroidism taking LT4 and PPIs or antacids, thus, require appropriate monitoring. The objective of this study was to determine whether a soft gelatin capsule of LT4 (Tirosint®) would obviate the effect of PPIs on LT4 absorption. The objective was achieved by assessing the effects of a switch from a conventional LT4 tablet form to the same dose as soft capsules in thyroidectomized patients on treatment with LT4 and PPIs. Methods: Patients with history of hypothyroidism due to total thyroidectomy on stable treatment with LT4 tablets, and with gastrointestinal disease treated with PPIs, were switched to a 12-week treatment with Tirosint at the same dose of the LT4 tablets, while maintaining treatment with PPIs. Serum thyrotropin (TSH) levels were the primary endpoint of the study. Secondary efficacy endpoints were: serum levels of free thyroxine (fT4), total thyroxine (TT4), free triiodothyronine (fT3), total triiodothyronine (TT3), creatine-phosphokinase (CPK), sex-hormone binding globulin, ferritin, angiotensin converting enzyme, and a lipid panel. Results: Forty-seven patients (36 females and 11 males, mean age 55.4 years) were enrolled and 45 of them completed the study (2 patients withdrew consent). During treatment with Tirosint, mean TSH levels demonstrated a statistically significant decrease (mean changes from baseline: -0.32 mIU/L at week 6 and -0.68 mIU/L at week 12) and concomitant increases in thyroid hormone (TH) levels from baseline to week 12, which were statistically significant for fT3 and TT3 (mean changes from baseline: 0.26 pmol/L and 0.10 nmol/L, respectively). Significant decreases of serum low-density lipoprotein, total cholesterol, and CPK levels were observed at week 12. No signs/symptoms arose during the study that could be specifically correlated to either hypo- or hyperthyroidism. Conclusions: In thyroidectomized patients taking PPIs and replacement LT4, a switch from conventional LT4 tablets to LT4 soft capsules at the same dose was associated with a significant decrease in TSH and increase in TH, indicating that LT4 absorption may be less affected by PPIs when given in the form of soft capsules. Clinical Trial Registration: NCT03094416.

Characteristics, staging and outcomes of differentiated thyroid cancer in patients with and without Graves' disease.

Background: The incidence of thyroid cancer has increased over the last three decades with studies showing incidence of thyroid cancer is higher among patients with Graves' Disease (GD) when compared to Toxic multinodular goiter.1 We conducted a retrospective study to further investigate characteristics and outcomes in patients with thyroid cancer and GD. Methods: We retrospectively reviewed 62 patients with a diagnosis of Differentiated Thyroid Cancer (DTC). We compared age at diagnosis, type, size of tumor, radioactive iodine (RAI) use, and DTC recurrence amongst patients with GD, non-GD patients. We used Chi-square to test for independence among categorical variables at a nominal level of 0.05; comparison was based on t-test. Results: Out of 62 patients, 29 patients had GD and DTC (47%). 94% had papillary thyroid cancer. Patients with GD were diagnosed with DTC at a younger age (mean 46 years) in comparison to patients without GD (mean 53 years). There was no difference in the type of DTC. Patients with GD had significantly smaller tumor size (mean size 1.035 cm; p value = 0.002), more Stage 1 and 2 compared to patients without GD (p-value = 0.009). Both groups of patients had similar rates of recurrence on follow up and RAI use. Conclusion: We found patients with GD had smaller tumor size, early-stage DTC when compared to patients without GD and potentially favorable prognosis. More data is needed to understand whether this is due to pathogenesis like Graves antibodies promoting tumor formation or merely earlier detection of DTC in GD.

Redifferentiation of Differentiated Thyroid Cancer: Clinical Insights from a Narrative Review of Literature.

Background: Patients who have metastatic differentiated thyroid cancer (mDTC) frequently have negative diagnostic and/or post-therapy radioiodine scans. As a result, 131I therapy is frequently no longer considered a therapeutic option for these patients. However, with the knowledge of genomic alterations of patients with mDTC, the use of selected agents in specific patient groups may be used with the intention to re-establish 131I uptake (i.e., redifferentiation) and additional 131I therapy. The objectives of this narrative review are to present definitions of related terminology, a brief overview of the molecular mechanisms of redifferentiating agents, and a narrative review of the literature for redifferentiation in patients who have radioiodine refractory mDTC. Summary: We searched multiple electronic databases and reviewed the relevant English-language literature reported after 2010. Fourteen articles were included in this narrative review. Conclusions: Preliminary data suggest that select agents may offer potential for re-establishing 131I uptake in selected patients with radioiodine refractory mDTC (e.g., negative diagnostic and/or post-therapy radioiodine scans). These agents may also enhance uptake (e.g., uptake enhancement) in patients who have 131I uptake in mDTC on a diagnostic and/or post-therapy radioiodine scan. As a result, this may facilitate higher absorbed dose delivered (Gy (rad]) per 131I activity administered [GBq (mCi)]. This in turn may increase the likelihood of a better therapeutic effect for the planned administered 131I activity or a reduction in the originally planned administered 131I activity, while achieving the same intended therapeutic effect with potentially less untoward effects. Further studies are warranted to confirm these preliminary observations and to confirm acceptable subsequent 131I therapy responses after redifferentiation and/or uptake enhancement.

Efficacy of machine learning to identify clinical factors influencing levothyroxine dosage after total thyroidectomy.

BACKGROUND: We employed Machine Learning (ML) to evaluate potential additional clinical factors influencing replacement dosage requirements of levothyroxine. METHOD: This was a retrospective study of patients who underwent total or completion thyroidectomy with benign pathology. Patients who achieved an euthyroid state were included in three different ML models. RESULTS: Of the 487 patients included, mean age was 54.1 ± 14.1 years, 86.0% were females, 39.0% were White, 53.0% Black, 2.7% Hispanic, 1.4% Asian, and 3.9% Other. The Extreme Gradient Boosting (XGBoost) model achieved the highest accuracy at 61.0% in predicting adequate dosage compared to 47.0% based on 1.6 mcg/kg/day (p < 0.05). The Poisson regression indicated non-Caucasian race (p < 0.05), routine alcohol use (estimate = 0.03, p = 0.02), and osteoarthritis (estimate = -0.10, p < 0.001) in addition to known factors such as age (estimate = -0.003, p < 0.001), sex (female, estimate = -0.06, p < 0.001), and weight (estimate = 0.01, p < 0.001) were associated with the dosing of levothyroxine. CONCLUSIONS: Along with weight, sex, age, and BMI, ML algorithms indicated that race, ethnicity, lifestyle and comorbidity factors also may impact levothyroxine dosing in post-thyroidectomy patients with benign conditions.

Lipid Profile Changes Associated with SGLT-2 Inhibitors and GLP-1 Agonists in Diabetes and Metabolic Syndrome.

The introduction of sodium glucose transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists in type 2 diabetes mellitus treatment has shown an unexpectedly significant improvement in heart disease outcome trials. Although they have very different modes of action, a portion of the salutary cardiovascular disease improvement may be related to their impact on diabetic dyslipidemia. As discussed in this focused review, the sodium glucose transporter-2 inhibitors as a class show a mild increase in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels, while triglycerides (TG) decrease inconsistently. In particular, the rise in LDL appears to be related to the less atherogenic, large buoyant LDL particles. The glucagon-like peptide-1 receptor agonists show more of an impact on weight loss and improvement in the underlying low HDL and high TG dyslipidemia. The effect of sodium glucose transporter-2 inhibitors and glucagon-like peptide 1 receptor agonists when used in combination remains largely unknown. Also unexplored is difference in effect of these medications among various ethnicities and metabolic syndrome.

Metastatic Differentiated Thyroid Cancer Survival Is Unaffected by Mode of Preparation for 131I Administration.

Context: Recombinant human thyrotropin (rhTSH) is currently not Food and Drug Administration approved for the treatment of high-risk patients with differentiated thyroid cancer (DTC). Objective: The goal of our study was to compare the outcomes in higher-risk patients with metastatic DTC prepared for radioiodine (RAI) therapy with rhTSH vs thyroid hormone withdrawal (THW). Methods: A retrospective chart review was performed of patients with metastatic DTC in follow-up at MedStar Washington Hospital Center and MedStar Georgetown University Hospital from 2009 to 2017. Patients were divided according to their preparation for RAI therapy, with assessment of progression-free survival (PFS) and overall survival (OS). Results: Fifty-five patients with distant metastases (16 men, 39 women) were prepared for RAI therapy exclusively either with rhTSH (n = 27) or with THW (n = 28). There were no statistically significant differences between the groups regarding clinicopathological features and history of RAI therapies. The median follow-up time for patients with rhTSH-aided therapies was 4.2 years (range, 3.3-5.5 years) and for patients with THW-aided therapies was 6.8 years (range, 4.2-11.6 years) (P = .002). Multivariate analysis showed that the method of thyrotropin stimulation was not associated with a difference in PFS or OS. Conclusion: As has been shown previously for low-risk DTC, this study indicates that the mode of preparation for RAI therapy does not appear to influence the outcomes of patients with metastatic DTC. PFS and OS were similar for patients with THW-aided or rhTSH-aided RAI therapies.

Clinical Factors Predictive of Lymph Node Metastasis in Thyroid Cancer Patients: A Multivariate Analysis.

BACKGROUND: Early-stage thyroid cancers have excellent survival. However, lymph node metastases (LNM) confer a worse prognosis and are not always known preoperatively. Therefore, investigation on the clinical and histological factors predictive of LNM in thyroid cancers was conducted to tailor the extent of surgery and radioactive iodine therapy. STUDY DESIGN: Multivariate logistic regressions were performed based on retrospective data from thyroid cancer patients seen between 2013 and 2020 at a single institution. RESULTS: Among 913 patients, mean age was 49.4 years, 76.5% were female, 58.3% were White, 21.2% were Black, and 27.9% had LNM. In the multivariate analyses in which the outcome was LNM, White (odds ratio [OR] 1.74, 95% CI 0.98 to 3.15, p = 0.064) and Hispanic patients (OR 2.36, 95% CI 0.97 to 5.77, p = 0.059) trended toward higher risk of LNM compared to Black patients, whereas age (OR 0.98, 95% CI 0.97 to 1.00, p = 0.008) showed protective effect. Tumor size (OR 1.04, 95% CI 1.01 to 1.07, p = 0.007), extrathyroidal extension (OR 2.46, 95% CI 1.53 to 3.97, p < 0.001), lymphovascular invasion (OR 6.30, 95% CI 3.68 to 11.14, p < 0.001), and multifocality (OR 1.47, 95% CI 1.01 to 2.12, p = 0.042) were associated with higher risk of LNM. In another model with outcome as >5 LNM, tumor size (OR 1.07, 95% CI 1.03 to 1.11, p = 0.001), age (OR 0.95, 95% CI 0.93 to 0.97, p < 0.001), extrathyroidal extension (OR 3.20, 95% CI 1.83 to 5.61, p < 0.001), and lymphovascular invasion (OR 6.82, 95% CI 3.87 to 12.17, p < 0.001) remained significant predictors. CONCLUSION: Our analyses demonstrated and confirmed that age, tumor size, extrathyroidal extension, and lymphovascular invasion are independent predictors of significant LNM, thereby conferring higher risk of recurrence. Risk of LNM based on these patient characteristics should be considered when planning an operative approach.

Sex Differences in Differentiated Thyroid Cancer.

Background: Sex dimorphism strongly impacts tumor biology, with most cancers having a male predominance. Uniquely, thyroid cancer (TC) is the only nonreproductive cancer with striking female predominance with three- to four-fold higher incidence among females, although males generally have more aggressive disease. The molecular basis for this observation is not known, and current approaches in treatment and surveillance are not sex specific. Summary: Although TC has overall good prognosis, 6-20% of patients develop regional or distant metastasis, one third of whom are not responsive to conventional treatment approaches and suffer a 10-year survival rate of only 10%. More efficacious treatment strategies are needed for these aggressive TCs, as tyrosine kinase inhibitors and immunotherapy have major toxicities without demonstrable overall survival benefit. Emerging evidence indicates a role of sex hormones, genetics, and the immune system in modulation of both risk for TC and its progression in a sex-specific manner. Conclusion: Greater understanding of the molecular mechanisms underlying sex differences in TC pathogenesis could provide insights into the development of sex-specific, targeted, and effective strategies for prevention, diagnosis, and management. This review summarizes emerging evidence for the importance of sex in the pathogenesis, progression, and response to treatment in differentiated TC with emphasis on the role of sex hormones, genetics, and the immune system.

Comparing the rate and extent of malignancy in surgically excised thyroid nodules across race and ethnicity.

BACKGROUND: Few studies have compared the features of thyroid cancer among races and ethnicities. We hypothesized that race and ethnicity may influence the frequency and features of thyroid malignancy in thyroid nodules. METHOD: This was a retrospective chart review of patients between 2013 and 2020 who underwent thyroidectomy. RESULTS: In the analysis of 2737 patients, thyroid cancer was less prevalent among Blacks (24.0% vs Whites 52.1%, Hispanics 58.7%, Asians 71.7%, and Others 57.9%, p < 0.001). Thyroid cancer in Blacks was less likely to have extrathyroidal extension (9.7% vs Whites 18.6%, Hispanics 25.8%, Asians 18.2%, and Others 17.8%, p = 0.01), overall nodal involvement (12.4% vs Whites 31.1%, Hispanics 37.5%, Asians 36.3%, and Others 30.1%, p < 0.01), and lateral neck metastasis (4.4% vs Whites 10.8%, Hispanics 6.3%, Asians 13.2%, and Others 9.6%, p = 0.02). CONCLUSIONS: Race and ethnicity may play important roles in the risk of malignancy as well as in the extent of thyroid cancer.

Do Ultrasound Patterns and Clinical Parameters Inform the Probability of Thyroid Cancer Predicted by Molecular Testing in Nodules with Indeterminate Cytology?

Background: Molecular testing (MT) is commonly used to refine cancer probability in thyroid nodules with indeterminate cytology. Whether or not ultrasound (US) patterns and clinical parameters can further inform the risk of thyroid cancer in nodules predicted to be positive or negative by MT remains unknown. The aim of this study was to test if clinical parameters, including patient age, sex, nodule size (by US), Bethesda category (III, IV, V), US pattern (American Thyroid Association [ATA] vs. American College of Radiology Thyroid Image Reporting and Data System [TI-RADS] systems), radiation exposure, or family history of thyroid cancer can modify the probability of thyroid cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) predicted by MT. Methods: We studied 257 thyroid nodules in 232 patients from 10 study centers with indeterminate fine needle aspiration cytology and informative MT results using the ThyroSeq v3 genomic classifier (TSv3). Univariate and multivariate logistic regression was used for data analysis. Results: The presence of cancer/NIFTP was associated with positive TSv3 results (odds ratio 61.39, p < 0.0001). On univariate regression, patient sex, age, and Bethesda category were associated with cancer/NIFTP probability (p < 0.05 for each). Although ATA (p = 0.1211) and TI-RADS (p = 0.1359) US categories demonstrated positive trends, neither was significantly associated with cancer/NIFTP probability. A multivariate regression model incorporating the four most informative non-MT covariates (sex, age, Bethesda category, and ATA US pattern; Model No. 1) yielded a C index of 0.653; R2 = 0.108. When TSv3 was added to Model number 1, the C index increased to 0.888; R2 = 0.572. However, age (p = 0.341), Bethesda category (p = 0.272), and ATA US pattern (p = 0.264) were nonsignificant, and other than TSv3 (p < 0.0001), male sex was the only non-MT parameter that potentially contributed to cancer/NIFTP risk (p = 0.095). The simplest and most efficient clinical model (No. 3) incorporated TSv3 and sex (C index = 0.889; R2 = 0.588). Conclusions: In this multicenter study of thyroid nodules with indeterminate cytology and MT, neither the ATA nor TI-RADS US scoring systems further informed the risk of cancer/NIFTP beyond that predicted by TSv3. Although age and Bethesda category were associated with cancer/NIFTP probability on univariate analysis, in sequential nomograms they provided limited incremental value above the high predictive ability of TSv3. Patient sex may contribute to cancer/NIFTP risk in thyroid nodules with indeterminate cytology.

Biotin Interference in Assays for Thyroid Hormones, Thyrotropin and Thyroglobulin.

Background: Biotin has been reported to interfere with several commonly used laboratory assays resulting in misleading values and possible erroneous diagnosis and treatment. This report describes a prospective study of possible biotin interference in thyroid-related laboratory assays, with a comparison of different commonly used assay platforms. Materials and Methods: Thirteen adult subjects (mean age 45 ± 13 years old) were administered biotin 10 mg/day for eight days. Blood specimens were collected at three time points on day 1 and on day 8 (baseline, two, and five hours after biotin ingestion). Thyrotropin (TSH), free triiodothyronine (fT3), free thyroxine (fT4), total triiodothyronine (TT3), total thyroxine (TT4), thyroxine binding globulin (TBG), and thyroglobulin (Tg) levels were analyzed with four different platforms: Abbott Architect, Roche Cobas 6000, Siemens IMMULITE 2000, and liquid chromatography with tandem mass spectrometry (LC-MS/MS). TSH, fT3, fT4, TT3, and TT4 were measured with Abbott Architect and Roche Cobas 6000. fT3, fT4, TT3, and TT4 were also measured by LC-MS/MS. Tg was measured by Siemens IMMULITE 2000. TBG was assessed with Siemens IMMULITE 2000. Results: Significant changes in TSH, fT4, and TT3 measurements were observed after biotin exposure when the Roche Cobas 6000 platform was used. Biotin intake resulted in a falsely lower Tg level when measurements were performed with Siemens IMMULITE 2000. At the time points examined, maximal biotin interference was observed two hours after biotin exposure both on day 1 and day 8. Conclusions: A daily dose of 10 mg was shown to interfere with specific assays for TSH, fT4, TT3, and Tg. Physicians must be aware of the potential risk of erroneous test results in subjects taking biotin supplements. Altered test results for TSH and Tg can be particularly problematic in patients requiring careful titration of levothyroxine therapy such as those with thyroid cancer.

Do Molecular Profiles of Primary Versus Metastatic Radioiodine Refractory Differentiated Thyroid Cancer Differ?

Management of metastatic radioiodine refractory differentiated thyroid cancer (DTC) can be a therapeutic challenge. Generally, little is known about the paired molecular profile of the primary tumor and the metastases and whether they harbor the same genetic abnormalities. The present study compared the molecular profile of paired tumor specimens (primary tumor/metastatic sites) from patients with radioiodine refractory DTC in order to gain insight into a possible basis for resistance to radioiodine. Twelve patients with radioiodine refractory metastases were studied; median age at diagnosis of 61 years (range, 25-82). Nine patients had papillary TC (PTC), one had follicular TC (FTC), and two had Hürthle cell TC (HTC). Distant metastases were present in the lungs (n = 10), bones (n = 4), and liver (n = 1). The molecular profiling of paired tumors was performed with a panel of 592 genes for Next Generation Sequencing, RNA-sequencing, and immunohistochemistry. Digital microfluidic PCR was used to investigate TERT promoter mutations. The genetic landscape of all paired sites comprised BRAF, NRAS, HRAS, TP53, ATM, MUTYH, POLE, and NTRK genes, including BRAF and NTRK fusions. BRAF V600E was the most common point mutation in the paired specimens (5/12). TERT promoter mutation C228T was detected in one case. PD-L1 expression at metastatic sites was highly positive (95%) for one patient with HTC. All specimens were stable for microsatellite instability testing, and the tumor mutation burden was low to intermediate. Therefore, the molecular profile of DTC primary and metastatic lesions can show heterogeneity, which may help explain some altered responses to therapeutic intervention.

Optimal Time for 124I PET/CT Imaging in Metastatic Differentiated Thyroid Cancer.

BACKGROUND: The objective of this study was to determine the optimal time for 124I PET/CT imaging to maximize the detection of locoregional and/or distant metastases of differentiated thyroid cancer. METHODS: Differentiated thyroid cancer patients suspected of having metastatic disease were prepared with low-iodine diet and appropriate thyroid-stimulating hormone stimulation. 124I PET and low-dose localization CT were performed over 4 days after oral administration of 31.5 or 62.9 MBq (0.85 or 1.7 mCi) of 124I. Each scan was independently reviewed by 2 nuclear medicine physicians. All foci of activity were categorized, and the visual intensity of uptake was scored by a semiquantitative 3-point grading system (1: mild uptake, 2: moderate uptake, 3: intense uptake). Lesion volumes were determined on the CT image or on the PET images. Background (bkg) was also measured for each lesion and on each individual PET image. For each lesion, the mean activity concentration rate per unit administered activity (ACRmean/AA) and lesion-to-bkg ratios were compared across the 5 different time points. The semiquantitative grade and the quantitative measurements were compared. RESULTS: A total of 45 124I PET/CT scans were reviewed for 9 patients. In the visual assessment, a total of 31 foci suggestive for or highly suggestive of metastasis were identified on 124I PET/CT. Of these, 6 were seen on the 2-h, 18 on the 24-h, 27 on the 48-h, 24 on the 72-h, and 20 on the 96-h scan. There was a significant difference between the 24- and 48-h scans in the total number of foci (ie, locoregional and distant metastasis) (P < 0.05) and in the number of distant metastases (P < 0.05). The 24-, 48-, and 72-h scans identified the same number of locoregional foci. The 48-h scan visualized more of the distant metastases than any other time point. 124I PET/CT with dual-time-point imaging was superior to single-time-point imaging (97% vs 87%). In the quantitative analysis, the median ACRmean/AA was highest at 24 and 48 h, and the median lesion-to-bkg ratio was variable for different lesion locations. For lung metastases, the highest median lesion-to-bkg ratio was at 72 and 96 h. CONCLUSIONS: 124I PET/CT with dual-time-point imaging was superior to any single-time-point imaging (P < 0.10). Based on the visual assessment, dual time points at 48 + 72 h or 48 + 96 h yielded the highest lesion detection rate, whereas for single-time-point imaging, the 48-h images had the highest lesion detection rate. If the 48-h scan is completely negative or has negative 124I uptake in the region of interest, then a 72- or 96-h scan may be valuable. If lung metastases are suspected, then one should consider additional imaging at 72 or 96 h.

The spectrum of 124I uptake in the lacrimal gland and nasolacrimal sac/duct on PET/CT imaging.

METHODS: 124I PET/CT in 31 DTC patients was performed at 2, 24, 48, 72, and 96 h after oral administration of 31.5 or 62.9 MBq (0.85 or 1.7 mCi) of 124I after either recombinant human thyroid-stimulating hormone injections or thyroid hormone withdrawal. All but two patients had a history of prior 131I therapy. Patterns of 124I uptake in the lacrimal glands and nasolacrimal sac/ducts (NLD) were assessed. RESULTS: A total of 173 individual 124I PET/CT scans (forming 35 sets of scans) were reviewed for 31 patients. Lacrimal glands were visualized bilaterally in only 4 patients. The focal mild uptake (grade 2), best seen on the 2-h images, was crescent-shaped and located in the lateral upper quadrant of the orbit. In contrast, the NLDs were identified in all patients (bilateral in 29 of 31 patients) with high focal uptake (grade 4) peaking on the 2- and 24-h timepoints; however, the overall pattern of uptake was variable. Of the 29 patients with prior 131I therapy, three patients had a relatively fixed and unchanging pattern of uptake on at least one side of the NLDs. CONCLUSIONS: In patients with DTC, 124I activity in the NLDs is more frequently visualized, more intense, more prolonged, and more variable than in the lacrimal glands. The lack of clearance may suggest possible obstruction or stasis of an NLD.

Evaluation and Treatment of Amiodarone-Induced Thyroid Disorders.

Amiodarone is a class III antiarrhythmic drug containing 37% iodine by weight, with a structure similar to that of thyroid hormones. Deiodination of amiodarone releases large amounts of iodine that can impair thyroid function, causing either hypothyroidism or thyrotoxicosis in susceptible individuals reflecting ~20% of patients administered the drug. Not only the excess iodine, but also the amiodarone (or its metabolite, desethylamiodarone) itself may cause thyroid dysfunction by direct cytotoxicity on thyroid cells. We present an overview of the epidemiology and pathophysiology of amiodarone-induced thyroid disorders, with a focus on the various forms of clinical presentation and recommendations for personalized management of each form.