<p><strong>Context: </strong>Thyroid nodules are increasingly recognized in children and are associated with a greater risk for thyroid cancer compared to adults. Thyroid ultrasound is the favored tool for evaluation of thyroid nodules; however, there are limited data regarding the accuracy of thyroid ultrasound to confirm features associated with a low risk of thyroid cancer in children.</p>

<p><strong>Objectives: </strong>We examined whether thyroid ultrasound is capable of accurately identifying thyroid nodules at a low risk of malignancy in children.</p>

<p><strong>Design and Setting: </strong>Using a retrospective cohort study design, we identified all children age ≤ 18 years with thyroid nodules and adequate follow up. Ultrasound images were reviewed independently by two blinded expert radiologists and ultrasound characteristics were analyzed to determine optimal predictive value and reliability.</p>

<p><strong>Patients and Results: </strong>417 subjects were found to have thyroid nodules and 152 subjects had adequate follow up; 59 (38.8%) of these were diagnosed with thyroid cancer. 236 individual nodules were evaluated. Features most consistent with benign nodules included small size, isoechoic echogenicity, partially cystic structure, sharp or non-infiltrative margins, absent Doppler flow and absent calcifications. Significant variability was found between expert interpretations of ultrasound features. Thyroid nodule composition appears to be the most sensitive and reliable feature for stratifying risk of thyroid cancer. Cumulatively, ultrasound accurately identified benign thyroid nodules in 80.9% (95% CI 74, 86.6%) of subjects.</p>

<p><strong>Conclusions: </strong>Ultrasonography is useful for the evaluation of thyroid nodules, but we found no combination of ultrasound features sufficient to exclude thyroid cancer without a biopsy.</p>

<p><strong>Context: </strong>In adults, non-invasive follicular variant papillary thyroid carcinoma (FVPTC) is considered low risk for metastasis and persistent/recurrent disease.</p>

<p><strong>Objective: </strong>The goal of this study was to assess the clinical, sonographic, and histopathological features of FVPTC in a pediatric cohort.</p>

<p><strong>Design: </strong>A retrospective review of subjects &lt; 19 years of age with papillary thyroid carcinoma (PTC) who underwent thyroidectomy between January 2010 and July 2015.</p>

<p><strong>Setting: </strong>Multidisciplinary, academic referral center.</p>

<p><strong>Patients: </strong>Patients with FVPTC, defined as a tumor ≥1.0 cm in largest dimension with predominant follicular growth, complete lack of well-formed papillae, and nuclear features of PTC.</p>

<p><strong>Main Outcome Measure: </strong>Tumor size and location, presence of a tumor capsule, capsule and vascular invasion, lymph node and distant metastasis.</p>

<p><strong>Results: </strong>Eighteen patients with FVPTC were identified from a case cohort of 110 patients with PTC. On histopathology, 13 (72%) had unifocal nodules and 14 (78%) were completely encapsulated. Capsule invasion was frequent (9/14; 64%) and vascular invasion was found in one third of patients (6/18; 33%). No lymph node metastases were found in the 13 (72%) patients who had a central neck lymph node dissection. One patient with vascular invasion had distant metastases.</p>

<p><strong>Conclusion: </strong>When strictly defined, FVPTC in pediatric patients has a low risk for bilateral disease and metastasis. Prospective studies are needed to confirm whether lobectomy with surveillance is sufficient to achieve remission in pediatric patients with low risk FVPTC.</p>