BACKGROUND: Although fine-needle aspiration (FNA) has an important role in evaluating thyroid nodules in adults, there is little published information regarding its utility in the pediatric population. METHODS: A retrospective analysis of thyroid FNAs for patients who were 18 years old or younger at 2 institutions was conducted. Aspirates were retrospectively categorized with the Bethesda System for Reporting Thyroid Cytopathology. These diagnoses were then correlated with either final histopathology or clinical follow-up. RESULTS: A total of 186 thyroid FNA samples from 154 patients (122 females and 32 males), who ranged in age from 9 months to 18 years (median, 16 years; mean, 14 years), were identified.FNA was performed to evaluate 1 to 3 nodules for each patient. Aspirates were classified as follows: nondiagnostic (n 5 27), benign (n 5 114), atypia of undetermined significance (AUS; n 5 21), follicular neoplasm (FN; n 5 8), suspicious for malignancy (n 5 3), and malignant (n 5 13). Sixty-one samples had a histologic correlation, 68 were followed clinically for 2 years, and 57 either had no follow-up or were followed for <2 years. For statistical purposes, FNA diagnoses of suspicious and malignant were considered positive, and benign lesions were considered negative. The accuracy was 99%, and the sensitivity and specificity were 94% and 100%, respectively. The risk of malignancy, not including papillary microcarcinoma, was 2% for benign aspirates, 21% for AUS, 57% for FN, and 100% for suspicious or malignant aspirates.CONCLUSIONS: This analysis demonstrates that FNA is a sensitive and highly specific modality for evaluating thyroid nodules in pediatric patients. Each diagnostic category can facilitate communication and guide appropriate management.

BACKGROUND The management of thyroid nodules with indeterminate cytology is challenging. Recently, molecular testing on fine‐needle aspirates (FNAs) has been advocated to determine whether clinical follow‐up or surgery is warranted for patients. Three different testing platforms were performed on aspirates from our institution (Afirma Thyroid FNA Analysis, RosettaGX Reveal, and Interpace ThyGenX/ThyraMIR). This study compares their diagnostic efficacy. METHODS We conducted a retrospective analysis of indeterminate thyroid FNAs with correlating molecular testing over 4 years (2015‐2018). The aspirates included diagnoses of follicular lesion of undetermined significance, follicular neoplasm, or suspicious for malignancy (SM). Based on cases that underwent surgical resection (Afirma, n = 37; Rosetta, n = 19; Interpace, n = 14), we calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for risk of malignancy and neoplasia. RESULTS The three tests performed similarly when predicting risk of malignancy. They showed high sensitivity (80‐100%) and NPV (90‐100%) but lower specificity (10‐64%) and PPV (21‐44%). When assessing their value to predict neoplasia, each test had a high PPV (76‐89%) but low NPV (20‐33%). The sensitivity for neoplasm was intermediate to high (50‐93%), and the specificity remained extremely variable (11‐67%). CONCLUSION Overall, these molecular platforms performed similarly, displaying high NPV but low to intermediate PPV for malignancy and low NPV but high PPV for neoplasm. The risk of neoplasm is a good index for surgery, and we argue that many of the neoplasms are low‐risk tumors. We endorse conservative treatment with lobectomy for cases that are indeterminate at FNA but suspicious by molecular testing.

This study demonstrates that two molecular testing platforms performed equally well using our stained direct smears. Both molecular tests revealed a 100% negative predictive rate. RosettaGX showed a 75% positive predictive value in comparison to 60% for ThyGenX/ThyraMIR.

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Background: The introduction of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) altered the practice of thyroid pathology and reduced the risk of malignancy (ROM) associated with the indeterminate categories in the Bethesda system for reporting thyroid cytopathology (TBSRTC). It has been proposed that the evaluation of the risk of neoplasm (RON) is important in cytologichistologic correlation studies. Methods: A total of 5224 thyroid aspirates were performed at our institution during an 8-year period. Of the 1475 cases (28%) with surgical follow-up, the histologic diagnoses comprised benign non-neoplastic (BNN, n = 669), follicular adenoma (FA, n = 188), NIFTP (n = 42), papillary microcarcinoma (PMC) (n = 223), and malignant neoplasm excluding PMC (n = 353). The RON was calculated to include neoplasia with low risk biologic behavior (FA, NIFTP, PMC) and malignant neoplasms. In contrast, the ROM was reserved for malignant neoplasms excluding PMC. Results: The RON for each TBSRTC category was: nondiagnostic (ND) 38.3%, benign 20.9%, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) 63.2%, follicular neoplasm or suspicious for follicular neoplasm (FN/SFN) 83.9%, suspicious for malignancy (SFM) 94%, and malignant 100%. The ROM excluding PMC was: ND 14%, benign 1.6%, AUS/FLUS 17.8%, FN/SFN 28.4%, SFM 84.4%, and malignant 99.5%. Conclusions: The RON and ROM support the recommended management guidelines from TBSRTC for all categories, except for FN/SFN. Histopathologic follow-up of FN/SFN aspirates in our study contain a very high rate of neoplasm (83.9%), which might support the management preference of conservative surgery. K E Y W O R D S cytology, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), risk of malignancy (ROM), risk of neoplasm, the Bethesda system for reporting thyroid cytopathology (TBSRTC), thyroid