Diana S. Dean

Prognostic indicators in differentiated thyroid carcinoma.

BACKGROUND Thyroid cancer ranges from well-differentiated lesions with an excellent prognosis to anaplastic carcinoma, which is almost uniformly fatal. Thus, methods to assess the behavior of thyroid malignancies are necessary to arrive at appropriate treatment decisions. METHODS We discuss the factors that affect the prognosis of patients with well-differentiated thyroid malignancies, including papillary, follicular, Hürthle cell, and medullary thyroid carcinomas. We also review the presentation, therapy, and outcome of patients seen at our center over a span of 50 years. These data have identified those prognostic factors that are predictive of survival and recurrence in differentiated thyroid cancer. RESULTS Several classifications with different variables have been developed to define risk-group categories. Three widely used systems, in addition to the TNM staging system, include AGES, AMES, and MACIS. CONCLUSIONS A better understanding of independently important prognostic variables will result in improved patient care and treatment.

Reliability of benign fine needle aspiration cytology of large thyroid nodules

BACKGROUND With increasing use of thyroid ultrasonography, thyroid nodules have been found to be extremely common. For over 25 years, fine needle aspiration (FNA) has been the pivotal diagnostic test to discriminate benign from potentially malignant thyroid nodules. Recently, false negative rates exceeding 10% have led to recommendations that thyroid nodules >/=4 cm should be resected regardless of cytology results. Our aim was to determine the false negative rate of FNA cytology on thyroid nodules >/=3 cm interpreted as benign at our institution. METHODS A retrospective review was performed at Mayo Clinic from January 2002 through December 2006. RESULTS From 6,921 ultrasonographic-guided thyroid FNAs, 742 were interpreted as benign and >/=3 cm. A definitive histologic diagnosis was available for 145 (20%) patients who underwent thyroidectomy: 1 (0.7%) was false negative. No additional thyroid malignancies were identified in 550 index nodules with average follow-up of 3 years. CONCLUSION With precise ultrasonographic-guided aspiration, strict adherence to guidelines for adequacy of the sample, proper cytologic preparation, and most importantly, expert cytologic analysis, a diagnosis of benign is extremely reliable for thyroid nodules, regardless of size. Resection for diagnosis is not necessary, and a size >/=3 cm should not be an independent indication for resection.

Risks and benefits of parathyroid fine-needle aspiration with parathyroid hormone washout.

OBJECTIVE To describe the experience with parathyroid fine-needle aspiration (FNA) and parathyroid hormone (PTH) washout at Mayo Clinic Rochester, Rochester, Minnesota. METHODS We retrospectively reviewed all parathyroid FNA procedures performed at Mayo Clinic Rochester between January 2000 and December 2007. Clinical, biochemical, and imaging information, parathyroid FNA procedure, and cytology, surgical, and pathology reports were reviewed, and descriptive statistics, sensitivity, specificity, and positive predictive values are presented. RESULTS During the study period, 75 parathyroid FNAs were performed on 74 patients. Cytology results were available for 74 of 75 procedures, with only 31% interpreted as parathyroid cells. PTH washout was performed in 67 patients (91%). Parathyroid FNA with PTH washout had a sensitivity of 84%, specificity of 100%, positive predictive value of 100%, and accuracy of 84%. At the time of surgical treatment, 2 patients were noted to have an inflammatory response from the parathyroid FNA biopsy, 1 had a parathyroid abscess, and 2 had a hematoma. In 3 of these 5 patients, the necessary conversion of a minimally invasive surgical procedure to the standard surgical approach prolonged the surgical time. CONCLUSION Parathyroid FNA with PTH washout had a superior performance in comparison with parathyroid scanning or ultrasonography alone. The main limitations of parathyroid FNA with PTH washout are (1) the need for initial identification of a potential parathyroid adenoma by ultrasonography and (2) the number of false-negative results. Parathyroid FNA resulted in complications affecting the surgical procedure in 3 patients.

Cloning of the mouse sodium iodide symporter.

The iodide-concentrating ability of the thyroid gland is essential to the production of thyroid hormone. We report the nucleotide and amino acid sequence of the mouse sodium iodide symporter (mNIS), which mediates this activity within the thyroid gland. An open reading frame of 1,857 nucleotides codes for a protein of 618 amino acids with 95% identity to rat NIS and 84% identity to human NIS. Transient expression of the mNIS cDNA in Chinese hamster ovary (CHO) cells, a nonthyroid cell line, resulted in sodium-dependent, perchlorate-sensitive iodide uptake. Western blot analysis of membrane preparations of CHO cells transiently transfected with mNIS cDNA showed a band of 90 kd when probed with an antibody directed against rat NIS. mNIS will serve as an important reagent in determining the role of NIS in experimental thyroid diseases and for monitoring the immune response to in animal models of NIS-mediated gene therapy.

Development and application of magnetic resonance elastography of the normal and pathological thyroid gland in vivo

To noninvasively assess the shear stiffness of the thyroid gland in vivo in order to determine whether magnetic resonance elastography (MRE) might hold clinical utility in the diagnosis of thyroid disease.

Prevalence and predictors of thyroid functional abnormalities in newly diagnosed AL amyloidosis

Data on the effect of systemic immunoglobulin light chain amyloidosis (AL amyloidosis) on thyroid function are limited.

Three cases of dermatomyositis associated with papillary thyroid cancer.

OBJECTIVE Dermatomyositis (DM) is considered a paraneoplastic phenomenon and cancer may precede or follow the development of clinical features by several years. Despite the prevalence of thyroid cancer, reports of an association are rare. We report 3 cases of dermatomyositis and thyroid cancer, focusing on the clinical course of the rheumatologic condition following thyroidectomy. We also performed a comprehensive review of the current literature. METHODS We performed a chart review between 1960 and 2012 to identify patients with DM and papillary thyroid cancer (PTC) seen in Mayo Clinic, Rochester, in Minnesota, a tertiary referral center. Only 3 patients were identified using the above criteria. RESULTS There was a significant improvement in the course of the dermatological condition after definitive treatment for thyroid cancer (i.e. thyroidectomy) in one of our patients. The risk of a first malignancy is highest at the time the diagnosis of dermatomyositis is made and remains significantly higher in the first two years following diagnosis. A comprehensive literature review identified only two patients with PTC and dermatomyositis (both in Taiwan) across 4 international population cohorts. In addition, several cases have been reported from patients in the Far East, a geographical predilection that is unexplained. CONCLUSIONS Our case series highlights the uncommon association between thyroid cancer and dermatomyositis while illustrating prevailing knowledge about the temporal relationship between dermatomyositis and thyroid cancer. Increased vigilance for and treatment of thyroid cancer in patients with dermatomyositis may assist in the successful management of this difficult rheumatologic condition.

Parathyroidectomy-induced thyroiditis.

OBJECTIVE To highlight the possibility of development of thyroiditis after parathyroidectomy. METHODS Clinical and laboratory findings in 2 cases are presented, and the relevant literature is reviewed. RESULTS In 2 women (84 years old and 55 years old) with no history of thyroid disease in one of them and a remote history of excision of a follicular adenoma in the other, thyrotoxicosis developed a few days to a week after parathyroidectomy for primary hyperparathyroidism. The first patient underwent bilateral cervical exploration with removal of a right inferior parathyroid adenoma, whereas the second patient had excision of 3 1/2 parathyroid glands for 4-gland hyperplasia and 2 benign nodules from the left thyroid lobe. Both surgical procedures were uncomplicated. Neither patient had received any iodinated contrast agents or medications such as lithium or amiodarone before presentation. Laboratory results showed elevated levels of free thyroxine, suppressed thyroid-stimulating hormone levels, very low radioiodine uptake (in the second patient), and an elevated thyroglobulin level (in the first patient). Both patients were treated symptomatically with beta-adrenergic antagonists. Thyroid function normalized and symptoms diminished after 1 to 2 months. CONCLUSION Parathyroidectomy-induced thyroiditis is underrecognized. The majority of patients are asymptomatic, although clinically significant thyrotoxicosis can also occur. Candidates for parathyroidectomy should be informed of this potential complication, and thyroid function should be assessed if clinically indicated.

Ultrasound-Guided Fine-Needle Aspiration Biopsy of Thyroid Nodules in Patients Taking Novel Oral Anticoagulants

BACKGROUND Ultrasound-guided fine-needle aspiration biopsy (USGFNAB) is the most accurate form of evaluation for thyroid nodules. Many patients with thyroid nodules who present for USGFNAB are on anticoagulant agents, including the novel oral anticoagulants (NOACs), for stroke prevention in atrial fibrillation or venous thrombosis prophylaxis. SUMMARY There has been at least one retrospective study describing neck USGFNAB bleeding risks in patients on antithrombotic and/or anticoagulant agents. This study concluded that there was no major bleeding risk or increase in hematoma formation in patients on antithrombotic or anticoagulant agents while undergoing USGFNAB, and there was no need to discontinue these agents prior to the procedure. With the emergence of NOACs, further recommendations should be made for patients on these agents who will be undergoing USGFNAB for thyroid nodules. Currently, there are no published studies regarding patients on NOACs who undergo USGFNAB. CONCLUSIONS It has previously been established that patients on historical anticoagulant agents do not need to discontinue therapy prior to minor procedures such as needle aspirations or dental procedures. Therefore, in patients currently taking dabigatran, rivaroxaban, or apixaban, it is concluded that it is reasonable and safe to continue the novel oral anticoagulant agents prior to USGFNAB of thyroid nodules without major risk of bleeding. This conclusion is based not only on the fact that minor procedures are considered safe in patients on NOACs, but also because patients on historical anticoagulant agents do not need to discontinue therapy prior to minor procedures.

Outcomes of Radiofrequency Ablation Therapy for Large Benign Thyroid Nodules: A Mayo Clinic Case Series

Objective: To assess the effectiveness, tolerability, and complications of radiofrequency ablation (RFA) in patients with benign large thyroid nodules (TNs). Patients and Methods: This is a retrospective review of 14 patients with predominantly solid TNs treated with RFA at Mayo Clinic in Rochester, Minnesota, from December 1, 2013, through October 30, 2016. All the patients declined surgery or were poor surgical candidates. The TNs were benign on fine‐needle aspiration, enlarging or causing compressive symptoms, and 3 cm or larger in largest diameter. We evaluated TN volume, compressive symptoms, cosmetic concerns, and thyroid function. Results: Median TN volume reduction induced by RFA was 44.6% (interquartile range [IQR], 42.1%‐59.3%), from 24.2 mL (IQR, 17.7‐42.5 mL) to 14.4 mL (IQR, 7.1‐19.2 mL) (P<.001). Median follow‐up was 8.6 months (IQR, 3.9‐13.9 months). Maximum results were achieved by 6 months. Radiofrequency ablation did not affect thyroid function. In 1 patient with subclinical hyperthyroidism due to toxic adenoma, thyroid function normalized 4 months after ablation of the toxic nodule. Compressive symptoms resolved in 8 of 12 patients (67%) and improved in the other 4 (33%). Cosmetic concerns improved in all 8 patients. The procedure had no sustained complications. Conclusion: In this population, RFA of benign large TNs performed similarly to the reports from Europe and Asia. It induces a substantial volume reduction of predominantly solid TNs, improves compressive symptoms and cosmetic concerns, and does not affect normal thyroid function. Radiofrequency ablation has an acceptable safety profile and should be considered as a low‐risk alternative to conventional treatment of symptomatic benign TNs.