Thyroid nodules are a common clinical problem with the widespread use of ultrasonography. Fine needle aspiration (FNA) is the mainstay for diagnosing a thyroid malignancy. There have been several guidelines on when to perform FNA in thyroid nodules. This review is based on several published recommendations and helps physicians easily understand the factors favoring FNA.
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The aging process is associated with progressive loss of muscle mass and strength, as well as decline in physical functioning. Although consensus diagnosis has not been reached, sarcopenia is increasingly defined by both loss of muscle mass and loss of muscle function or strength. The cause of sarcopenia is suggested as multifactorial, including hormonal changes, inflammatory pathway activation, fatty infiltration, poor nutrition, and decreased physical activity. Sarcopenia is often associated with visceral obesity. Sarcopenic obesity in the elderly impacts metabolic complications and represents a major public health challenge in a rapidly aging society. Further research about sarcopenia and sarcopenic obesity may be needed to confront the influence of aging society in Korea.
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Several epidemiologic studies suggested that osteoporosis and osteoporotic fractures are not uncommon in South Korea. However, these previous cohort studies had limitations that may have influenced their results and the generalizability of the study conclusions, including small sample sizes, inclusion of only women, enrollment of participants from specific areas, and nonrandom selection of participants. Recently, epidemiologic studies using a nationwide claim register have been performed to overcome these limitations through collaboration between the Korean Society of Bone and Mineral Research and Health Insurance Review Assessments. Our review of the Korean Nationwide-database Osteoporosis Study could be helpful to obtain accurate incidence and prevalence estimations of osteoporosis and osteoporosis-related fractures in Korea.
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The role of adiposity in the relationship between serum vitamin D levels and insulin resistance has not yet been fully studied. This aim of this study is to clarify the role of adiposity in the relationship between serum vitamin D level and insulin resistance among middle-aged and elderly Korean adults.
We used data from 2,710 individuals aged ≥50 years based on national data from a representative sample of the fourth Korea National Health and Nutrition Examination Survey IV-2 in 2008.
After adjustment for potential confounders, body mass index (BMI) was significantly associated with 25(OH) vitamin D (
Our results support that the idea that endogenously-produced vitamin D might be stored in subcutaneous fat deposits. In addition, the association of vitamin D with insulin resistance in middle-aged and elderly Korean adults was stronger when it was stratified by BMI than when abdominal obesity status.
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Several studies have suggested that elevated levels of hemoglobin A1c (HbA1c) are associated with cardiovascular disease (CVD) in nondiabetic individuals. However, it is unclear whether HbA1c levels can serve as a simple screening marker for increased CVD risk in nondiabetic individuals. Our objective was to evaluate the relationship between HbA1c levels and CVD risk using the Framingham risk score (FRS) in older, apparently healthy nondiabetic Korean adults.
We retrospectively studied 2,879 Korean adults between the ages of 40 and 79 who underwent voluntary health check-ups at the Health Promotion Center of our hospital from July 2009 to June 2011. Subjects were subdivided based on their HbA1c levels into four groups: tertiles within the HbA1c normal tolerance range and a group for subjects with an increased risk for diabetes (IRD).
The mean FRS for the upper tertile (9.6±3.8) group was significantly higher than that of the middle tertile (8.4±4.0) and lower tertile (7.6±3.8) groups. In addition, FRS was highest in the IRD group (10.5±3.7). Multiple linear regression analysis demonstrated that HbA1c levels exhibited a significant positive correlation with FRS when adjusted for confounding variables in all subjects (β±standard error [SE], 0.018±0.002;
HbA1c levels were positively correlated with FRS in older, apparently healthy nondiabetic Korean adults. We propose that HbA1c levels may reflect CVD risk in nondiabetic individuals.
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The natural course of cytologically benign thyroid nodules remains unclear. The aim of this study was to evaluate whether ultrasonographic (US) changes are associated with changes in nodule volume during follow-up.
We retrospectively reviewed over 4 years of clinical records of patients with benign thyroid nodules as confirmed by fine needle aspiration (FNA). In total, 186 patients with 202 benign thyroid nodules were included for study. We assessed for changes in nodule volume and examined the cystic portion of the nodule as well as four US features (echogenicity, margin, calcification pattern, and shape).
During follow-up (mean, 21.7±10.7 months) and using 50% as a cutoff value, nodule volumes increased in 11.8%, exhibited no change in 79.9%, and decreased in 8.3% of patients. Proportion of nodules demonstrating at least one US change was 20.8% (42/202). The most common US changes (in descending order of frequency) were cystic change, margin change, and calcification pattern change. Nodule shape and echogenicity rarely changed. Increased nodule volume was not significantly associated with any US features or with the number of FNAs but was associated with younger age at time of diagnosis.
Although a portion of thyroid nodules confirmed as benign showed US changes or volume changes during the follow-up period, these findings may only represent the natural course of benign nodules. Frequent follow-up with US might be needed for only a small number of cases with suspicious US findings.
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We analyzed whether thyroid stimulating hormone receptor (TSH-R) is expressed in a skeletal muscle cell line and if TSH has influence on the differentiation of muscle cells or on the determination of muscle fiber types.
TSH-R gene expression was detected with nested real-time polymerase chain reaction (RT-PCR) in C2C12, a mouse skeletal muscle cell line. The effect of TSH on myotube differentiation was assessed by microscopic examination of myotube formation and through the measurement of expression of muscle differentiation markers, i.e., myogenin and myoD, and muscle type-specific genes, i.e., MyHC1, MyHC2a, and MyHC2b, with quantitative RT-PCR before and after incubation of C2C12 myotube with TSH.
TSH-R was expressed in the mouse skeletal muscle cell line. However, treatment with TSH had little effect on the differentiation of muscle cells, although the expression of the muscle differention marker myogenin was significantly increased after TSH treatment. Treatment of TSH did not affect the expression of muscle type-specific genes.
TSH-R is expressed in a mouse skeletal muscle cell line, but the role of TSH receptor signaling in skeletal muscle needs further investigation.
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Recent studies suggested that the association of acute glucose variability and diabetic complications was not consistent, and that A1c variability representing long term glucose fluctuation may be related to coronary atherosclerosis in patients with type 1 diabetes. In this study, we attempt to determine whether or not A1c variability can predict coronary artery disease (CAD) in patients with type 2 diabetes.
We reviewed data of patients with type 2 diabetes who had undergone coronary angiography (CAG) and had been followed up with for 5 years. The intrapersonal standard deviation (SD) of serially-measured A1c levels adjusted by the different number of assessments among patients (adj-A1c-SD) was considered to be a measure of the variability of A1c.
Among the 269 patients, 121 of them had type 2 diabetes with CAD. In patients with A1c ≥7%, the mean A1c levels and A1c levels at the time of CAG among the three groups were significantly different. The ratio of patients with CAD was the highest in the high adj-A1c-SD group and the lowest in the low adj-A1c-SD group (
Patients with higher A1c variability for several years showed higher mean A1c levels. A1c variability can be an independent predictor for CAD as seen in angiographs of patients with type 2 diabetes with mean A1c levels over 7%.
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A 48-year-old woman was incidentally found to have bilateral adrenal masses, 2.8 cm in diameter on the right, and 2.3 cm and 1.7 cm in diameter on the left, by abdominal computed tomography. The patient had a medical history of hypertension, which was not being controlled by carvedilol, at a dose of 25 mg daily. She presented with signs and symptoms that suggested Cushing Syndrome. We diagnosed adrenocorticotropic hormone (ACTH)-independent Cushing Syndrome based on the results of basal and dynamic hormone tests. Adrenal vein sampling (AVS) was performed to localize a functioning adrenal cortical mass. AVS results were consistent with hypersecretion of cortisol from both adrenal glands, with a cortisol lateralization ratio of 1.1. Upon bilateral laparoscopic adrenalectomy, bilateral ACTH-independent adrenal adenomas were found. The patient's signs and symptoms of Cushing Syndrome improved after surgery just as the blood pressure was normalized. After surgery, the patient was started on glucocorticoid and mineralocorticoid replacement therapy.
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Riedel's thyroiditis is a rare form of infiltrative and inflammatory disease of the thyroid gland and can be associated with systemic fibrotic processes, Hashimoto thyroiditis and Graves disease. Riedel thyroiditis in combination with Graves disease however, is very rare. A 57-year-old woman with a past medical history significant for Graves disease diagnosed 30 years ago presented with an enlarging neck mass and voice changes. Due to suspicion of malignancy, thyroidectomy was performed. Histopathologic examination revealed Riedel thyroiditis. To our knowledge, the association of Riedel thyroiditis with Graves disease has not yet been reported in our country. Here we report a patient with Riedel thyroiditis evolved from antecedent Graves disease.
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Although pathology reports of thyroid tissue in ovarian teratomas are abundant, benign teratomas of the thyroid are extremely rare in adolescents and adults. Therefore, their clinical characteristics are still not well characterized. We report a case of a 54-year-old woman with a growing mass in her neck. Left lobectomy of the thyroid revealed it to be a benign thyroid teratoma composed of tissues from all three germ layers. Preoperative evaluations included thyroid ultrasonography (US), ultrasound-guided fine needle aspiration cytology (FNAC), and computed tomography (CT) of the neck. A 4.7-cm, well defined, predominantly hypoechoic mass intermingled with hyperechoic internal lesions, was observed in the inferior portion of the left thyroid lobe with substernal extension on US. The posterior extent of the nodule was not visualized due to deep attenuation of the echo. US-guided FNAC failed to reveal any thyroid follicular cells, but suggested a benign cystic tumor. Neck CT hinted at the diagnosis of teratoma because the mass contained large amounts of fat, and the margin was well defined. Extrathyroidal extension and cervical lymphadenopathy were not seen. She underwent left thyroid lobectomy, and histologic examination confirmed benign thyroid teratoma. To the best of our knowledge, this is the first case report of benign thyroid teratoma in Korea.
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We report a rare case of severe hypoglycemia after sunitinib treatment for pancreatic neuroendocrine carcinoma. We describe the initial clinical presentation, laboratory results, pathologic findings, and managment in a patient with a nonfunctioning pancreatic neuroendocrine carcinoma with liver metastases who developed life threatening hypoglycemia after 2 months of sunitinib therapy. A 46-year-old woman presented to the emergency department with loss of consciousness from hypoglycemia. Serum C-peptide and insulin levels at fasting state revealed that the hypoglycemia resulted from endogenous hyperinsulinemia. She had been diagnosed with nonfunctioning pancreatic neuroendocrine carcinoma based on a biopsy of metastatic cervical lymph node and was being treated with sunitinib, a small molecule tyrosine kinase inhibitor. Immunohistochemical stain of the metastatic liver mass demonstrated that the initially nonfunctioning neuroendocrine carcinoma cells had changed into insulin-producing cells after sunitinib therapy. Transarterial chemoembolization of the liver masses and systemic chemotherapy with streptozotocin/adriamycin relieved the hypoglycemia. A nonfunctioning pancreatic neuroendocrine carcinoma was transformed into an insulin-producing tumor after treatment with sunitinib, causing endogenous hyperinsulinemia and severe hypoglycemia.
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