A Case of Riedel’s Thyroiditis Treated with Tamoxifen: Another Successful Outcome

ObjectiveTo report a case of Riedel’s thyroiditis, which was successfully treated with tamoxifen.MethodsWe present the clinical, laboratory, and imaging findings and describe the clinical course of a patient with Riedel’s thyroiditis.ResultsA 40-year-old woman presented with hypothyroidism and a large goiter, which was unresponsive to hormone replacement therapy. Magnetic resonance imaging confirmed the presence of an enlarged thyroid gland, more pronounced on the right than on the left. The patient had progressive discomfort attributable to compressive symptoms in the neck. Surgical exploration of the neck disclosed a hard, immobile thyroid mass, which could not be resected because of adherence to surrounding structures. Biopsy of the thyroid and of the muscles of the neck revealed Riedel’s thyroiditis. Treatment with tamoxifen, in a dosage of 20 mg twice a day for more than 1½ years, completely resolved the neck mass (substantiated by follow-up magnetic resonance imaging) and relieved the signs and symptoms of compression of the neck.ConclusionTamoxifen treatment is effective in resolving the mass and compression in Riedel’s thyroiditis. (Endocr Pract. 2004;10:483-486)     

Unusual Clinical Course of Graves’ Thyrotoxicosis and Concomitant Sarcoidosis: Case Report and Review of Literature

ObjectiveTo report a case of Graves’ disease with concomitant sarcoidosis involving the thyroid gland.MethodsWe present the clinical, laboratory, imaging, and pathologic findings and describe the clinical course of a patient with Graves’ disease and sarcoidosis, who was unresponsive to propylthiouracil and radioiodine treatment.ResultsA 23-year-old woman presented with thyrotoxicosis and a large goiter. Laboratory studies and findings on thyroid uptake and scan were consistent with Graves’ disease. She was also found to have hilar lymph-adenopathy and hepatosplenomegaly. Despite treatment with antithyroid drugs and radioiodine therapy, her hyperthyroidism persisted. Surgical resection of the thyroid gland and 2 lymph nodes disclosed noncaseating granulomas, consistent with sarcoid.ConclusionAutoimmune endocrinopathies and, less commonly, thyroid autoimmune disease have been reported in patients with sarcoidosis. Similarities exist in the pathogenesis of these two conditions. Concomitant sarcoidosis in the thyroid gland in patients with Graves’ disease may contribute to the resistance to antithyroid drugs and radioiodine therapy. (Endocr Pract. 2007;13:159-163)     

Hyalinizing trabecular tumor in a background of lymphocytic thyroiditis: a challenging neoplasm of the thyroid

ObjectiveTo describe a case of hyalinizing trabecular tumor (HTT) in a background of lymphocytic thyroiditis that was misdiagnosed as papillary thyroid carcinoma (PTC) based on fine-needle aspiration (FNA) cytologic findings and overtreated with total thyroidectomy.MethodsWe present a case report, including the imaging and pathologic findings, of a 68-year-old woman who presented with a multinodular goiter that was suspicious for PTC.ResultsOn the basis of FNA cytologic findings, she underwent a total thyroidectomy, and histologic examination of the thyroid gland revealed HTT in a background of lymphocytic thyroiditis. Radioiodine treatment was not administered because of the tumor’s low risk profile. No metastatic foci were established under nonsuppressive levothyroxine therapy after 3 years of follow-up.ConclusionsHTT is a challenging entity because of the uncertainty of its nature, the diagnostic challenges,and the mimicry of other types of thyroid tumors. In order to avoid overtreatment, endocrinologists and thyroid surgeons should be aware of the features of HTT, and suspicious cases should be evaluated by experienced cytopathologists. (Endocr Pract. 2011;17:e140-e143)     

Thyroid: an Unusual Hideout for Sarcoidosis

ObjectiveTo present a case of dysphagia secondary to a progressively increasing nontoxic multinodular goiter caused by sarcoidosis.MethodsWe summarize the clinical presentation and pertinent pathology in a patient with sarcoidosis involving the thyroid gland. A review of literature regarding this topic is also presented.ResultsA 54-year-old man was noted to have asymptomatic nontoxic thyromegaly. Biopsy of right thyroid nodule was benign while the biopsy from the isthmus nodule was nondiagnostic. He presented with acute onset of dysphagia two months later and the work-up for gastrointestinal causes was negative. Chest imaging showed left-sided lymphadenopathy, and biopsy of a lymph node showed sarcoidosis. Two years after the initial presentation a repeat biopsy of the isthmus nodule was again reported as nondiagnostic. Because he had persistent dysphagia, he underwent total thyroidectomy with resolution of dysphagia. Histopathological examination of the thyroid revealed non necrotizing granulomas consistent with sarcoidosis.ConclusionThis case brings to light this uncommon etiology of a nontoxic multinodular goiter. Involvement of the thyroid gland by sarcoidosis is very rare. It has been reported in 4.2 to 4.6% of patients with sarcoidosis. In patients with pulmonary or extrapulmonary sarcoidosis and associated thyromegaly, possible involvement of the thyroid by this process should be considered. (Endocr Pract. 2013;19:e40-e43)     

Erlotinib-Associated Exacerbation of Hypothyroidism with Pericardial Tamponade

ObjectiveTo report a case of erlotinib-associated exacerbation of hypothyroidism complicated by pericardial tamponade.MethodsWe describe the patient’s clinical presentation, biochemical workup, and clinical course.ResultsNon-small cell lung cancer was diagnosed in a 54-year-old woman. After cisplatin and radiation therapy, she was noted to have subclinical hypothyroidism that did not necessitate treatment. The tyrosine kinase inhibitor erlotinib, 150 mg once daily, was prescribed. Three months later, the patient was documented to have severe hypothyroidism. Levothyroxine was prescribed, but she continued to experience shortness of breath, fatigue, and chest and back pain, which resulted in an emergency department visit. Inpatient workup revealed cardiac tamponade with a large pericardial effusion and a right ventricular diastolic collapse. Pericardiocentesis was performed.ConclusionsThis is the first case report linking erlotinib use and thyroid disease. (Endocr Pract. 2012; 18:e111-e113)     

Plasma cell granuloma of the tongue. Report of a case

A case of plasma cell granuloma of the tongue in an otherwise symptomless 48-year-old caucasian female is reported. The polyclonal nature of the plasmocytes was revealed by immunostaining of kappa and lambda light chains. Electron microscopic observations showed typical mature plasmocytes. A parasitic etiology of this type of lesion is suggested.     

Over Hypothyroidism in a Woman Undergoing Controlled Ovarian Hyperstimulation

ObjectiveThyroid function and gonadal axis are related throughout a woman’s fertile period. Modifications of thyroid hormone levels have been reported as a consequence of controlled ovarian stimulation for infertility.MethodsA 28-year-old woman with regular menses and previous evidence of euthyroidism underwent controlled ovarian hyperstimulation (COH) for assisted reproductive technology (ART). Free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), and autoantibodies against thyroperoxidase and thyroglobulin (TPOAb and TgAb, respectively) were measured before COH. FT4, FT3, and TSH were re-evaluated 6 days, 2 weeks (during oocyte retrieval), and 1 month after the beginning of the procedure.ResultsThe baseline evaluation revealed subclinical autoimmune hypothyroidism. The patient was hypothyroidic at 6 days and 2 weeks and spontaneously returned to euthyroidism 1 month after COH.ConclusionThis is the first case of a woman with an unknown subclinical autoimmune hypothyroidism who developed overt and transient hypothyroidism as a consequence of COH. Careful thyroid evaluation is advised for women undergoing COH. (Endocr Pract. 2014;20:e11-e13)     

Intrathyroidal Parathyroid Carcinoma as Cause of Hypercalcemia and Pitfall of Localization Techniques: Clinical and Biologic Features

ObjectiveTo describe an unusual case of intrathyroidal parathyroid carcinoma (PC), which was retrospectively diagnosed in a woman who underwent surgical treatment of a recurrent nodular goiter.MethodsWe report the clinical and biologic features of an intrathyroidal PC, discuss the challenges with distinguishing PC from parathyroid adenoma, and review the related literature.ResultsA 67-year-old woman sought medical attention for dysphagia attributable to the recurrence of a normal functioning multinodular goiter. Thyroid ultra-sonography disclosed a 3-cm solid inferior nodule. Because she refused surgical treatment and a trial of levothyroxine was unsuccessful, periodic follow-up examinations were scheduled. At 1-year follow-up, hypercalcemia (12.1 to 12.6 mg/dL) and low phosphorus levels (2.0 to 2.3 mg/dL) were found, and parathyroid hormone (PTH) levels were profoundly increased (481 to 721 pg/mL). Neck ultrasonography showed a large hypoechogenic solid nodule, not clearly cleaved from the right thyroid lobe, which was possibly compatible with an enlarged parathyroid gland; however, a sestamibi scan was negative. During total thyroidectomy, intraoperative frozen sections of the intrathyroid nodule were compatible with nodular goiter with cellular pleomorphism. Final histologic examination showed cellular nests with nuclear pleomorphism and invasive behavior into the thyroid tissue and likely into the vessels, in conjunction with immuno-histochemical negativity for thyroglobulin and strong positivity for PTH. These findings were highly suggestive of and supported the diagnosis of PC. Postoperatively, calcium levels normalized, and PTH values declined considerably but remained slightly increased. Vitamin D supplementation helped normalize the PTH levels. The patient has undergone follow-up for 5 years and has shown no morphologic or biochemical signs of tumor recurrence.ConclusionPC is a rare entity but should be suspected in patients with hypercalcemia, substantially increased PTH levels, and a neck mass. In such patients, techniques such as sestamibi scanning may fail to localize the neoplasm. Surgical treatment remains the preferred technique for an optimal outcome of the disease. Nevertheless, lifelong follow-up is necessary. (Endocr Pract. 2007;13:176-181)     

Metastatic Renal Cell Carcinoma to the Thyroid Gland

ObjectiveTo examine the presentation, diagnosis, and appropriate management of renal clear cell carcinoma metastasis to the thyroid gland.MethodsWe describe a clinical case of solitary thyroid metastasis from renal clear cell carcinoma and present a comprehensive review of the related English-language literature. Common patterns of presentation and generalized overall management recommendations are evaluated and summarized.ResultsEight years after nephrectomy for renal carcinoma at age 61 years, a man presented with a thyroid mass. Cytology and histopathologic surgical findings were consistent with a solitary metastasis most compatible with metastatic clear cell carcinoma from his previous renal carcinoma. After left thyroid lobectomy and isthmusectomy, the patient remains disease-free 5 years later. Although uncommon, nearly 150 cases of clinically recognized metastatic renal cell carcinoma to the thyroid have been reported in the English-language literature. Metastatic disease from the kidney to the thyroid gland can occur more than 20 years after nephrectomy with the average time interval being 7.5 years. Obtaining a full clinical history in any patient who presents with a thyroid nodule is essential to allow consideration of possible metastatic disease from previous primary tumor. Metastatic disease to the thyroid gland can be correctly diagnosed preoperatively. If metastatic renal cancer is limited to the thyroid gland only, prompt, appropriate surgical intervention can be curative.ConclusionMetastatic renal carcinoma to the thyroid should be considered in any patient presenting with a thyroid mass and a medical history of renal cell carcinoma. (Endocr Pract. 2008;14:1040-1046)     

Evidence of Endemic Goiter and Iodine Deficiency in a Mountainous Area of Haiti

ObjectiveTo investigate reports of iodine-deficiency disorder in a specific area of Haiti.MethodsIn March 2008, this cross-sectional study was performed in an area 15 miles northeast of Jacmel, Haiti, within the Chaîne de la Selle Mountains. Before arrival of the study team, an announcement was made throughout local villages soliciting volunteers to meet at a central location. Of those who arrived, participants were selected in an attempt to sample individuals from all age groups, regardless of goiter status. After providing verbal informed consent, each participant was photographed and assigned a number to be used to protect privacy. An examiner performed palpation of the thyroid gland on each participant in accordance with World Health Organization criteria. Results of palpation were classified into 3 grades: grade 0, the thyroid gland was not palpable; grade 1, the thyroid gland was palpable but not visible; and grade 2, the thyroid gland was palpable and visible while the patient was in a normal position. Casual urine samples were collected from each participant and analyzed spectrophotometrically for urinary iodine concentration.ResultsEighty-eight individuals aged 2 to 72 years participated in the study. Median urinary iodine concentration was 39 μg/L. Of the 88 participants, 82 (93%) were iodine deficient (18 [20%] were severely deficient), and 45 (51%) had goiter on physical examination, including 27 with grade 1 goiters and 18 with grade 2 goiters.ConclusionsWe have documented iodine deficiency with associated endemic goiter in this previously uninvestigated Haitian population, for which world health agencies currently lack definitive data. These data have potential implications for both the local area and the country as a whole where further evaluation and treatment are needed for persons at high risk for iodine-deficiency disorder. (Endocr Pract. 2009;15:298-301)     

Role of Bamboo-Shoot in the Pathogenesis of Endemic Goiter in Manipur,North East India

ObjectiveEndemic goiter is prevalent in the iodine-sufficient region of Manipur, India. Bamboo shoot (BS), a goitrogenic plant food, are consumed regularly in the area. The objective of this study was to examine the role of BS in the pathogenesis of endemic goiter.MethodsGoiter prevalence, urinary iodine, and thiocyanate (SCN) excretion in school children, iodine content in drinking water, and the household consumption of salt fortified with iodine were measured. To confirm the goitrogenic potential of BS, its progoitrogenic constituents were fed to rats as part of an iodine-sufficient diet, after which the animals' thyroid gland morphology and functional status were assessed.ResultsGoiter prevalence was 31% in 4852 children, and the median urinary I and SCN levels were 176.3 μg/L and 0.962 ± 0.190 mg/dL, respectively. Of the households assessed, 90% consumed salt fortified with adequate iodine. Progoitrogenic constituents were high in BS from Manipur. Increased thyroid weight, hypertrophy and hyperplasia of follicular cells, decreased thyroid peroxidase activity, and low serum thyroxine (T₄) and triiodothyronine (T₃) levels were observed in BS-fed rats.ConclusionNearly one third of the studied participants had palpable goiter, despite a successful salt iodine fortification program. SCN from BS causes goiter in iodine-sufficient experimental animals. Similar ingestion in study participants was confirmed and is the likely cause for the persistence of endemic goiter in the Manipur region. (Endocr Pract. 2013;19:36-45)     

Determinants of Long-Term Outcome after Radioiodine Therapy for Solitary Autonomous Thyroid Nodules

ObjectiveTo determine the incidence and clinical predictors of hypothyroidism in one institution after radioiodine treatment of solitary toxic nodules.MethodsWe retrospectively analyzed the outcome of radioiodine therapy in 105 patients with solitary autonomous thyroid nodules treated at our institution during a 10-year period (January 1996 to December 2005; mean duration of follow-up, 53 ± 34 months). Patients were monitored until the development of hypothyroidism, death, or the end of the study period. The cumulative incidence of hypothyroidism was determined by Kaplan-Meier life-table analysis, and predictors of hypothyroidism were determined by using a Cox regression model.ResultsThe cumulative incidence of hypothyroidism was 11% at 1 year, 33% at 5 years, and 49% at 10 years. The development of hypothyroidism was not associated with age, sex, radioiodine dose, radioiodine uptake, or degree of suppression of extranodal tissue on scintiscans. The predictors of occurrence of hypothyroidism were pretreatment with antithyroid medications (P = .004; relative risk = 1.94) and positive thyroid antibody status (P = .008; relative risk = 1.84). Antibody-positive patients showed an earlier progression toward hypothyroidism than did antibody-negative patients.ConclusionHypothyroidism is a common outcome of radioiodine treatment for autonomous thyroid nodules. In this study, coexistent thyroid autoimmunity and pretreatment with antithyroid medications were significant risk factors for the development of hypothyroidism. (Endocr Pract. 2008;14:543-549)     

Does Unilateral Lobectomy Suffice to Manage Unilateral Nontoxic Goiter?

ObjectiveTo evaluate the effectiveness of ipsilateral lobectomy to treat unilateral, nontoxic, benign nodular goiter and to define predictive factors for recurrence.MethodsPatients undergoing thyroid lobectomy for unilateral, nontoxic, benign nodular goiter between 2002 and 2007 were included. Patients were excluded if coincidental thyroid cancer was detected at histopathologic examination and completion thyroidectomy was performed. Potential predictors of recurrence including age; sex; family history; preoperative volume of the thyroid gland; preoperative number, size, and ultrasonography characteristics of the nodules; duration of postoperative follow-up; postoperative use of thyroxine; and histopathologic diagnoses were recorded at baseline. Follow-up visits were scheduled every 3 months during the first year and every 6 months thereafter. Recurrent disease was defined as a hypoechogenic or hyperechogenic nodule larger than or equal to 3 mm detected in the remaining contralateral lobe during ultrasonography. Patients with a thyrotropin value greater than 5 mIU/L received thyroxine. Fineneedle aspiration biopsy was performed for nodules greater than 10 mm or for nodules with characteristics suggestive of malignancy. Reoperation was indicated if a nodule was greater than 3 cm in diameter, posed a risk of malignancy, or caused compression signs or symptoms.ResultsA total of 104 patients were included. Histopathologic diagnoses at initial operation were adenoma in 45 patients, colloidal nodular goiter in 45 patients, and chronic lymphocytic thyroiditis in 14 patients. Average duration of follow-up was 39.75 ± 21.75 months (range, 5-87 months). Recurrence was seen in 63 patients (60.6%). Histopathologic characteristics of the lobectomy material (P <.001), preoperative volume of the thyroid gland (P <.006), and multinodularity (P <.011) were significant predictors of recurrence.ConclusionsHigher preoperative thyroid volume, histopathologic characteristics of nodules, and multinodular disease are associated with an increased risk of recurrence in patients with unilateral nodular goiter. Unilateral lobectomy is an effective therapeutic option with low reoperation rates in unilateral benign thyroid disease. (Endocr Pract. 2010;16:36-41)     

Rhabdomyolysis and Peroneal Nerve Compression Associated With Thyroid Hormone Withdrawal in the Setting of Remnant Ablation: Review of the Literature

ObjectiveTo review the putative mechanisms whereby hypothyroidism is associated with severe myopathy, neural injury, and acute compartment syndrome and report a case of nontraumatic common peroneal nerve compression associated with hypothyroidism-induced rhabdomyolysis in a patient with diabetes prepared for remnant ablation after thyroidectomy for differentiated thyroid carcinoma.MethodsWe performed a review of the Englishlanguage literature on the PubMed database using the terms hypothyroidism, muscle disease, hypothyroid myopathy, rhabdomyolysis, compression neuropathy, and acute compartment syndrome.ResultsMyopathy occurs frequently among patients with overt hypothyroidism; however, severe myoneural injury seems to be precipitated or accompanied by comorbid conditions. Focal peroneal neuropathy may be related to hypothyroidism-induced extrinsic compression from severe myopathy and soft tissue swelling in a narrowed fascial compartment.ConclusionSevere short-term iatrogenic hypothyroidism may lead to severe myopathy and compression nerve injury in patients with underlying diabetic neuropathy. We recommend avoidance of withdrawal of thyroid hormone for purposes of remnant ablation among patients with preexisting diabetic neuropathy. (Endocr Pract. 2011;17:629-635)     

Anaplastic Thyroid Cancer Manifesting as New-Onset Horner Syndrome

ObjectiveTo report a case of Horner syndrome as the initial sign of locally advanced anaplastic thyroid cancer.MethodsWe present a case report in conjunction with a retrospective review and evaluation of the English-language literature on Horner syndrome and thyroid pathologic conditions.ResultsHorner syndrome is a rare complication of thyroid disease most often occurring in the postoperative setting after resections. Preoperatively, Horner syndrome is usually caused by a benign intrathoracic goiter that compresses the sympathetic plexus as it exits the thoracic cavity to enter the neck. Malignant thyroid disease leading to Horner syndrome is less common than benign causes of the syndrome. Treatment of compressive lesions can lead to resolution of nerve compression.ConclusionHorner syndrome is a rare complication of thyroid pathologic conditions. When present preoperatively, the majority of cases are due to benign compression of the cervical plexus. Therefore, Horner syndrome in the setting of a goiter does not necessarily portend a malignant process as one might suspect. Nonetheless, it still remains important that those patients who present with Horner syndrome undergo appropriate assessment for detection of mass lesions, underlying vascular etiologic factors, or other potentially treatable disorders causing sympathetic chain dysfunction. (Endocr Pract. 2009;15:563-566)     

Autoimmune thyroid disease in patients with vitiligo: prevalence study in India

ObjectiveTo identify the prevalence of autoimmune thyroid disease (AITD) in Asian Indian patients with vitiligo and to compare the clinical profile between thyroid peroxidase (TPO) antibody-positive and TPO antibodynegative groups.MethodsIn this cross-sectional, case-controlled study, 50 patients with vitiligo (29 women and 21 men) were included. Patients with previous disorders, irradiation, or surgical procedures involving the thyroid were excluded from the study. All participants underwent a complete physical examination, and a single fasting blood sample was analyzed for thyroid function (triiodothyronine, thyroxine, thyroid-stimulating hormone, and TPO and thyroglobulin antibodies), inflammatory and immunologic markers (erythrocyte sedimentation rate, C-reactive protein, and rheumatoid factor), and serum calcium, phosphorus, and alkaline phosphatase concentrations. All patients underwent thyroid ultrasonography, and the data were analyzed by appropriate statistical methods.ResultsThe mean age of the study participants was 42.7 ± 17 years, and 14 of 50 patients (28%) had TPO antibody positivity. A goiter was present in 11 of 50 patients, and the thyroid volume by ultrasonography was similar between the 2 groups. Subclinical hypothyroidism was found in 14 of 50 patients (28%) but more frequently in the TPO antibody-positive group (8 of 14 or 57%) than in the TPO antibody-negative group (6 of 36 or 17%). The prevalence of AITD was 20 of 50 patients (40%) when the TPO antibody-positive group and those with subclinical hypothyroidism were considered collectively. None of the patients had overt hypothyroidism or hyperthyroidism. All other clinical, biochemical, and inflammatory variables did not differ significantly between the TPO antibody-positive and antibody-negative groups.ConclusionOur data showed a 40% prevalence of thyroid disease in patients with vitiligo in India. The risk is exacerbated in patients with thyroid autoimmunity; thus, regular screening of patients with vitiligo for AITD is needed. (Endocr Pract. 2012;18:194-199)     

Clinical Aspects of Hyperthyroidism,Hypothyroidism, and Thyroid Screening in Pregnancy

ObjectiveTo evaluate the peer-reviewed literature on hypothyroidism, hyperthyroidism, and thyroid autoimmunity in pregnancy.MethodsWe review published studies on thyroid autoimmunity and dysfunction in pregnancy, the impact of thyroid disease on pregnancy, and discuss implications for screening.ResultsOvert hyperthyroidism and hypothyroidism are responsible for adverse obstetric and neonatal events. Several studies of association suggest that either subclinical hypothyroidism or thyroid autoimmunity increase the risk of complications. One randomized controlled trial showed that pregnant women with subclinical hypothyroidism benefit from treatment in terms of obstetric and neonatal complications, whereas another study demonstrated no benefit in the intelligence quotient of babies born to women with subclinical hypothyroidism. Thyroid autoimmunity has been associated with increased rate of pregnancy loss, recurrent miscarriage, and preterm delivery.ConclusionCurrent guidelines agree that overt hyperthyroidism and hypothyroidism need to be promptly treated and that as potential benefits outweigh potential harm, subclinical hypothyroidism also requires substitutive treatment. The chance that women with thyroid autoimmunity may benefit from levothyroxine treatment to improve obstetric outcome is intriguing, but adequately powered randomized controlled trials are needed. The issue of universal thyroid screening at the beginning of pregnancy is still a matter of debate, and aggressive case-finding is supported. (Endocr Pract. 2014;20:597-607)     

Levothyroxine Pseudomalabsorption and Thyroxine Absorption Testing with Use of High-Dose Levothyroxine: Case Report and Discussion

ObjectiveTo report the case of a 55-year-old woman who had been prescribed a daily dose of 1, 000 μg of levothyroxine for the treatment of hypothyroidism but still had severe biochemical hypothyroidism and to discuss the use of thyroxine absorption testing to diagnose pseudomalabsorption.MethodsThe patient was admitted to the hospital for supervised thyroxine absorption testing. Baseline thyroid function tests were performed. An oral dose of 1, 000 μg of levothyroxine was administered while the patient had an empty stomach, and thyroid function tests were repeated at 2, 4, and 6 hours after administration. She was also given all her prescribed antihypertensive medications, and the blood pressure (which had been persistently high) was measured every 2 hours.ResultsAfter administration of 1, 000 μg of levothyroxine, a rapid improvement in the results of her thyroid function tests was noted. Similarly, a rapid decrease in her blood pressure was observed after supervised administration of her antihypertensive medications. A diagnosis of nonadherence to treatment (pseudomalabsorption of levothyroxine) was made. After reduction of her levothyroxine dosage to 100 μg daily, results of thyroid function tests showed improvement. The doses of her antihypertensive medications were likewise altered.ConclusionWe suggest that patients who are receiving doses of levothyroxine of more than 2 μg/kg of body weight, with persistently increased thyroid-stimulating hormone levels, should undergo testing for malabsorption and pseudomalabsorption of levothyroxine. Thyroxine absorption testing with use of high-dose levothyroxine is useful in diagnosing pseudomalabsorption but needs formal evaluation and validation. (Endocr Pract. 2010;16:1012-1015)     

Tyrosine Kinase Inhibitors and the Thyroid as Both an Unintended and an Intended Target

ObjectiveTo review the association of the tyrosine kinase inhibitor sunitinib with hypothyroidism as well as the mean time to onset, possible mechanisms, reversibility, and mean duration.MethodsWe performed a MEDLINE search of the English-language literature using a combination of words (“sunitinib,” “tyrosine kinase inhibitors,” “thyroid,” and “hypothyroidism”) to identify original studies and reviews on sunitinib and thyroid function.ResultsHypothyroidism was reported in 36% to 46% of patients who took sunitinib in prospective studies. A higher incidence (53% to 85%) was reported in studies containing both retrospective and prospective data. The mean time to onset of hypothyroidism after initiation of sunitinib therapy ranged from 12 to 50 weeks. The risk of development of hypothyroidism appears to increase with the increasing duration of sunitinib therapy, and the condition is likely reversible once therapy has been discontinued.ConclusionBaseline thyroid function tests should be performed before the initiation of sunitinib treatment. Because hypothyroidism can develop early in the course of therapy, thyroid function tests should be monitored frequently throughout the duration of treatment. Possible mechanisms for thyroid dysfunction include impaired thyroid hormone synthesis, a destructive thyroiditis preceding the development of hypothyroidism, and increased thyroid hormone clearance. If hypothyroidism is identified, levothyroxine therapy should be promptly initiated. (Endocr Pract. 2008;14:618-624)     

Incidental Thyroid Cancer in Toxic and Nontoxic Goiter: is TSH Associated with Malignany Rate? Results of A Meta-Analysis

ObjectiveIn the last 6 years, several studies reported a positive association between thyrotropin (TSH) and papillary cancer risk. The rationale is based on stimulatory action exerted by TSH on thyroid cell proliferation and/ or progression of a pre-existing papillary carcinoma. To validate this hypothesis, we performed a meta-analysis comparing the incidence of thyroid cancer in 2 groups of patients who underwent surgery for toxic or nontoxic nodular goiter.MethodsUsing data from 2,150 patients with toxic multinodular goiter (TMNG) and 873 patients with toxic adenoma (TA), the overall incidence of thyroid cancer (and 95% confidence interval [CIs]) was estimated to be 5.9% (3.9 to 8.3) for patients with TMNG and 4.8% (2.5 to 7.9) for patients with TA. Four studies were included in the meta-analysis with a total of 1,964 subjects undergoing thyroidectomy for allegedly benign thyroid disease (520 patients with TMNG or TA and 1,444 for multinodular goiter [MNG] or uninodular goiter [UNG]).ResultsWe did not find any significant differences in the risk of incidental thyroid cancer (ITC) in patients with TMNG versus MNG (odds ratio [OR]: 0.91, 95% CI: 0.47 to 1.77, I⁴: 62.6%), TA versus uninodular goiter (UNG) (OR: 0.46, 95% CI: 0.12 to 1.79, I⁵: 12%), and TMNG or TA versus MNG or UNG (pooled analysis) (OR: 0.86, 95% CI: 0.46 to 1.60, I⁶: 51.5%).ConclusionsThe results of this meta-analysis did not confirm an association between low TSH values and lower thyroid cancer rate, at least in patients with nodular disease. (Endocr Pract. 2013;19:212-218)