No abstract

In a patient with one or more thyroid nodules larger than 10 mm in diameter, the likelihood of thyroid cancer per patient is independent of the number of nodules, whereas the likelihood per nodule decreases as the number of nodules increases. For exclusion of cancer in a thyroid with multiple nodules larger than 10 mm, up to four nodules should be considered for FNA. Sonographic characteristics can be used to prioritize nodules for FNA based on their individual risk of cancer.

Levothyroxine requirements increase as early as the fifth week of gestation. Given the importance of maternal euthyroidism for normal fetal cognitive development, we propose that women with hypothyroidism increase their levothyroxine dose by approximately 30 percent as soon as pregnancy is confirmed. Thereafter, serum thyrotropin levels should be monitored and the levothyroxine dose adjusted accordingly.

Background: Increased recognition of the indolent nature of noninvasive follicular variant of papillary thyroid carcinoma (NFVPTC) along with greater insight into the molecular alterations of these tumors has prompted endocrine pathologists to question whether these tumors warrant a diagnosis of carcinoma. However, a change in terminology would affect the rates of malignancy of fine-needle aspiration (FNA) diagnostic categories. Therefore, the aim of this study was to determine the percentage decrease in associated risk of malignancy for each FNA diagnostic category if NFVPTCs were no longer termed carcinomas. Methods: We evaluated a cohort of 655 FNAs with subsequent resection specimens over a 22-month time period. The diagnoses of the preceding FNAs were recorded according to the Bethesda System for Reporting Thyroid Cytopathology. For cases with more than one preceding FNA, the FNA diagnosis associated with the highest risk of malignancy was identified. Slides for all resection specimens with a diagnosis of FVPTC were reviewed to identify noninvasive tumors. By definition, all of these tumors were encapsulated, partially encapsulated, or well circumscribed and lacked any indication of infiltrative growth, capsular penetration, or lymphovascular invasion. Results: Our cohort of 655 FNAs with subsequent resection specimens included 53 (8.1%) nondiagnostic (ND), 167 (25.5%) benign, 97 (14.8%) atypia/follicular lesion of undetermined significance (AUS/FLUS), 88 (13.4%) suspicious for follicular neoplasm (SFN), 94 (14.4%) suspicious for malignancy (SUS), and 156 (23.8%) malignant cases (POS). Surgical resections demonstrated benign findings in 309 (47.2%) and malignant tumors in 346 (52.8%), including 85 NFVPTCs accounting for 24.6% of malignancies. Our rates of malignancy for ND, benign, AUS/FLUS, SFN, SUS, and POS were 18.9%, 13.2%, 39.2%, 45.5%, 87.2%, and 98.7%, respectively. If NFVPTC were no longer termed carcinoma, these rates would drop to 17.0% (10% decrease), 5.4% (59% decrease), 21.6% (45% decrease), 37.5% (18% decrease), 45.7% (48% decrease), and 93.6% (5% decrease), respectively. Conclusion: Our findings demonstrate that if terminology were changed and NFVPTCs were not considered carcinomas, the rates of malignancy for FNA diagnostic categories would be substantially decreased, with the most clinically significant decrease seen in the SUS category, which demonstrated a relative decrease of nearly 50%.

In the Bethesda System for reporting thyroid fine-needle aspirations (FNAs), atypia of undetermined significance (AUS) is a category with limited reported follow-up and outcome data. We report a retrospective analysis of our institution's experience during nearly 4.5 years with a tiered classification scheme conforming to the Bethesda System in which repeated FNA was recommended for most patients with an initial AUS diagnosis. Of 4,691 thyroid FNAs, 512 (10.9%) had a diagnosis of AUS. Cytologic or histologic outcome data were available for 331 cases (64.6%), of which 240 (72.5%) were benign and 91 (27.5%) were malignant. Of patients with a surgical diagnosis, there was no statistically significant difference in malignancy rate among patients who went directly to surgery after a single AUS diagnosis (37/90 [41%]), patients having 2 successive AUS FNA diagnoses (22/51 [43%]), and patients with a benign aspirate after AUS (2/7 [29%]). Although AUS confers an intermediate risk of malignancy, guidelines recommending repeated FNA for most cases should be reevaluated.

Hypothyroidism is a frequent complication of sunitinib therapy. Regular surveillance of thyroid function is warranted in patients receiving the drug. Although the mechanism by which this complication occurs is unknown, the observations of preceding TSH suppression and subsequent absence of visualized thyroid tissue in some patients suggest that sunitinib may induce a destructive thyroiditis through follicular cell apoptosis. This provides a rationale for further investigation of sunitinib treatment in patients with advanced thyroid cancer.

Increasing thyroid nodule size impacts cancer risk in a nonlinear fashion. A threshold is detected at 2.0 cm, beyond which cancer risk is unchanged. However, the risk of follicular carcinomas and other rare thyroid malignancies increases as nodules enlarge.

Neck ultrasonography and biopsy were key to the evaluation of children with suspected thyroid nodules. Although the relative cancer prevalence of sonographically confirmed nodules ≥ 1 cm is higher in pediatric patients than adults, most children referred for suspected nodules have benign conditions, and efforts to avoid unnecessary surgery in this majority are warranted.