Ji In Lee

BRAFV600E Mutation Analysis in Fine-Needle Aspiration Cytology Specimens for Evaluation of Thyroid Nodule: A Large Series in a BRAFV600E-Prevalent Population

BACKGROUND The BRAFV600E mutation is highly specific to papillary thyroid carcinoma. A test for this mutation may increase the diagnostic accuracy of fine-needle aspiration cytology (FNAC), especially in a BRAFV600E mutation-prevalent population. METHODS This prospective study enrolled 1074 patients with thyroid nodules who underwent both FNAC and BRAFV600E mutation analysis by dual-priming oligonucleotide (DPO)-based multiplex PCR in FNA specimens. RESULTS The ancillary test for BRAFV600E significantly improved the sensitivity of FNA procedure, from 67.5% with FNAC alone to 89.6% with FNAC and the DPO-based multiplex PCR analysis combined. Diagnostic accuracy increased from 90.9 to 96.6%. Nine cases of papillary thyroid carcinoma were detected only by BRAFV600E mutation analysis. Unexpectedly, the preoperative DPO-based multiplex PCR produced five false-positive results, which surgery showed to represent benign nodules. CONCLUSIONS Molecular testing for the BRAFV600E mutation in FNA thyroid nodule specimens increases diagnostic value when applied in a BRAFV600E mutation-prevalent population. However, when using this potentially powerful technique, we must consider both its strengths and its weaknesses.

Parafibromin immunohistochemical staining to differentiate parathyroid carcinoma from parathyroid adenoma.

Parafibromin is a protein encoded by the HRPT2 oncosuppressor gene, and the expression is reported to be decreased or absent in parathyroid carcinomas.

Usefulness of iodine/creatinine ratio from spot-urine samples to evaluate the effectiveness of low-iodine diet preparation for radioiodine therapy

Objective  The success of a low‐iodine diet (LID) is best determined by measurement of 24‐h urine iodine (U‐I) excretion. The aim of this study was to determine reliable estimates for 24‐h U‐I based on spot‐urine samples and to provide cut‐offs to determine the effectiveness of LID preparation.

Characteristics of Killian-Jamieson diverticula mimicking a thyroid nodule.

Killian–Jamieson (K–J) diverticula have been incidentally detected on neck ultrasonography and could be misdiagnosed as thyroid nodules. The purpose of this study was to define the clinical and ultrasonographic characteristics of K–J diverticula.

BRAFV600E mutation in fine‐needle aspiration aspirates: Association with poorer prognostic factors in larger papillary thyroid carcinomas

Recent studies have shown that BRAFV600E mutation is associated with poor prognostic factors in papillary thyroid carcinoma (PTC). However, there are no studies about the association of the BRAFV600E mutation with poor prognostic factors according to tumor size in PTC.

A Case of Resistance to Thyroid Hormone with Thyroid Cancer

Resistance to thyroid hormone (RTH) is an autosomal dominant hereditary disorder that is difficult to diagnose because of its rarity and variable clinical features. The magnitude of RTH is caused by mutations in the thyroid hormone receptor beta (TRβ) gene. We recently treated a 38-yr-old woman with RTH who had incidental papillary thyroid carcinoma. She presented with goiter and displayed elevated thyroid hormone levels with an unsuppressed TSH. She was determined to harbor a missense mutation of M310T in exon 9 of the TRβ gene, and diagnosed with generalized RTH. This mutation has not yet been reported in Korea. RTH is very rare and easily overlooked, but should be considered in patients who present with goiter and elevated thyroid hormone levels with an unsuppressed TSH. The association between thyroid cancer and RTH needs further study.

Diagnostic accuracy of plasma free metanephrines in a seated position compared with 24-hour urinary metanephrines in the investigation of pheochromocytoma

The aim of this study was to determine the diagnostic efficacy of free metanephrines in plasma samples drawn in the seated position compared with 24-h urinary metanephrines in detecting pheochromocytomas in Asian patients. This prospective study was conducted at Samsung Medical Center between May 2010 and July 2011. The study contained 245 subjects, including 28 patients with histologically-proven pheochromocytoma, 44 with histologically-proven non-pheochromocytoma, 112 controls suspected of having tumors but with negative investigations during two or more years of follow-up, and 45 healthy normotensive volunteers. Plasma-free metanephrines were measured by LC-MS/MS. The cut-off values with optimal sensitivity and specificity for plasma metanephrine and plasma normetanephrine were 0.33 nmol/L and 0.61 nmol/L, respectively. Both the plasma metanephrines measurement and urinary metanephrines measurement had a sensitivity of 96.4% (p = 1.00). However, the urinary metanephrines measurement was significantly more specific than the plasma metanephrines measurement (94.2% vs. 75.6%; p < 0.001). When we applied cut-off values based on BMI, specificity improved from 75.6% to 87.2%, with a comparable gain in sensitivity. From a diagnostic perspective, measurement of free metanephrines in plasma drawn in the seated position is highly sensitive but insufficiently specific when compared with measurement of 24-h urinary fractionated metanephrines. The specificity may be improved by applying cut-off values based on BMI. We suggest that free metanephrines in plasma drawn from seated position can also be used as an initial screening test to ensure that pheochromocytomas are not missed in Asian patients.

Daily urine iodine excretion while consuming a low‐iodine diet in preparation for radioactive iodine therapy in a high iodine intake area

Objective  Recommended durations of low‐iodine diet (LID) in preparation for radioactive iodine therapy (RAIT) vary among major guidelines and are important for patients in areas where iodine intake is high. The aim of this study was to investigate daily changes in urine iodine excretion after starting a LID.

Differences in serum thyroglobulin measurements by 3 commercial immunoradiometric assay kits and laboratory standardization using Certified Reference Material 457 (CRM-457)

Serum thyroglobulin (Tg) is essential in the follow‐up of patients with differentiated thyroid carcinoma (DTC). However, interchangeability and standardization between Tg assays have not yet been achieved, even with the development of an international Tg standard (Certified Reference Material 457 [CRM‐457]).

Predictive factors of durability to sitagliptin: Slower reduction of glycated hemoglobin, older age and higher baseline glycated hemoglobin

The goal of the present study was to evaluate predictive factors for good efficacy and durability to sitagliptin with ongoing metformin or metformin plus glimepiride therapy in a real practice situation. The present observational study was carried out over a 60‐week period and involved Korean patients with type 2 diabetes mellitus.