Follicular patterned thyroid nodules with nuclear features of papillary thyroid carcinoma (PTC) encompass a range of diagnostic categories with varying risks of metastatic behavior. Subtypes include the invasive encapsulated follicular variant of PTC (Ienc-fvPTC) and infiltrative fvPTC (inf-fvPTC), with tumors lacking invasive features classified as noninvasive follicular thyroid neoplasms with papillary-like features (NIFTPs). This study aimed to report the clinical and histological features of pediatric cases meeting criteria for these histological subtypes, with specific focus on Ienc-fvPTC and inf-fvPTC. In this retrospective cohort study, pediatric patients with thyroid neoplasms showing follicular patterned growth and nuclear features of PTC noted on surgical pathology between January 2010 and January 2021 were retrospectively reviewed and classified according to the recent 2022 World Health Organization (WHO) criteria. Clinical and histopathologic parameters were described for NIFTP, Ienc-fvPTC, and inf-fvPTC subtypes, with specific comparison of Ienc-fvPTC and inf-fvPTC cases. The case cohort included 42 pediatric patients, with 6 (14%), 25 (60%), and 11 (26%) patients meeting criteria for NIFTP, Ienc-fvPTC, and inf-fvPTC, respectively. All cases were rereviewed, and 5 patients originally diagnosed with Ienc-fvPTC before 2017 were reappraised as having NIFTPs. The NIFTP cases were encapsulated tumors without invasive features, lymph node or distant metastasis, or disease recurrence. Ienc-fvPTC tumors demonstrated clearly demarcated tumor capsules and capsular/vascular invasion, while inf-fvPTC tumors displayed infiltrative growth lacking a capsule. inf-fvPTC cases had increased prevalence of malignant preoperative cytology, lymph node metastasis, and distant metastasis ( < 0.01). These cases were treated with total thyroidectomy, lymph node dissection, and subsequent radioactive iodine therapy. Preliminary genetic findings suggest a predominance of fusions in inf-fvPTC cases versus point mutations in Ienc-fvPTC ( = 0.02). Pediatric NIFTP and fvPTC subtypes appear to demonstrate alignment between clinical and histological risk stratification, with indolent behavior in Ienc-fvPTC and invasive features in inf-fvPTC tumors.

Follicular patterned thyroid nodules with nuclear features of papillary thyroid carcinoma encompass a range of diagnostic categories with varying risks of metastatic behavior. Subtypes include invasive encapsulated fvPTC (Ienc-fvPTC) and infiltrative fvPTC (inf-fvPTC) with tumors lacking invasive features classified as non-invasive follicular thyroid neoplasm with papillary-like features (NIFTP). This study aimed to report the clinical and histologic features of pediatric cases meeting criteria for these histological subtypes with specific focus on Ienc-fvPTC and inf-fvPTC. In this retrospective cohort study, pediatric patients with thyroid neoplasms showing follicular patterned growth and nuclear features of papillary thyroid carcinoma noted on surgical pathology between January 2010 and January 2021 were retrospectively reviewed and classified according to the recent 2022 World Health Organization (WHO) criteria. Clinical and histopathologic parameters were described for NIFTP, Ienc-fvPTC, and inf-fvPTC subtypes, with specific comparison of Ienc-fvPTC and inf-fvPTC cases. The case cohort included 42 pediatric patients, with 6 (14%), 25 (60%), and 11 (26%) patients meeting criteria for NIFTP, Ienc-fvPTC, and inf-fvPTC, respectively. All cases were re-reviewed, and 5 patients originally diagnosed with Ienc-fvPTC prior to 2017 were reappraised as NIFTP. The NIFTP cases were encapsulated tumors without invasive features, lymph node or distant metastasis, or disease recurrence. Ienc-fvPTC tumors demonstrated clearly demarcated tumor capsules and capsular/vascular invasion, while inf-fvPTC tumors displayed infiltrative growth lacking a capsule. Inf-fvPTC cases had increased prevalence of malignant pre-operative cytology, lymph node metastasis, and distant metastasis ( < 0.01). These cases were treated with total thyroidectomy, lymph node dissection, and subsequent radioactive iodine therapy. Preliminary genetic findings suggest a predominance of fusions in inf-fvPTC cases versus point mutations in Ienc-fvPTC ( < 0.01). Pediatric NIFTP and fvPTC subtypes appear to demonstrate alignment between clinical and histological risk stratification, with indolent behavior in Ienc-fvPTC and invasive features in inf-fvPTC tumors.

<p><strong>Importance: </strong>The current recommendation for pediatric patients with papillary thyroid cancer (PTC) is a total thyroidectomy. This recommendation applies to all stages of PTC, including papillary thyroid microcarcinoma (≤1 cm, T1a) tumors.</p>

<p><strong>Objective: </strong>To evaluate the characteristics of American Joint Committee on Cancer T1 PTC tumors in a large pediatric population and to identify a subgroup of patients who may benefit from a thyroid lobectomy instead of a total thyroidectomy.</p>

<p><strong>Design, Setting, and Participants: </strong>This retrospective cohort study was conducted from January 1, 2009, to May 31, 2020. The study took place at a tertiary care medical center and included 102 patients who were surgically treated for T1 PTC: 52 with stage T1a (≤1 cm) tumors and 50 with stage T1b (&gt;1 cm but ≤2 cm) tumors.</p>

<p><strong>Main Outcomes and Measures: </strong>Primary outcomes included the presence of bilateral disease and lymph node metastasis.</p>

<p><strong>Results: </strong>A total of 102 patients (mean age, 15.3 years [range, 9.7-18.9 years]; 84 girls [82.4%]) were included in the analysis. Among 52 patients with T1a tumors, 10 (19.2%) had bilateral disease, and 15 (28.8%) had central neck lymph node (N1a) metastasis. Among 50 patients with T1b tumors, 10 (20%) had bilateral and 13 (26%) had N1a disease. Of those with T1a, unilateral multifocality was associated with bilateral disease (odds ratio [OR], 2.1; 95% CI, 1.3-3.4) and N1a disease (OR, 5.1; 95% CI, 1.5-17.6). Both N1a disease (OR, 20.0; 95% CI, 3.5-115.0) and ≥4 positive lymph nodes (OR, 8.6; 95% CI, 1.2-60.9) were associated with bilateral disease. In patients with no pathologic evidence of lymph node metastasis (N0), there was a 95% rate of unilateral PTC. In patients with T1b tumors, unilateral multifocality was also associated with bilateral disease (OR, 1.8; 95% CI, 1.3-2.7). Patients with T1b tumors had an increased risk of lateral (N1b) neck lymph node metastasis when compared with those with T1a tumors (OR, 3.7; 95% CI, 1.0-14.5).</p>

<p><strong>Conclusions and Relevance: </strong>The findings of this cohort study suggest that, in patients with unifocal T1a PTC without clinically evident nodal disease on preoperative ultrasonography, a thyroid lobectomy and central neck dissection may be considered. If there is no evidence of unilateral multifocality or if there are fewer than 4 positive lymph nodes on postoperative pathology, then close observation may be considered. These findings have substantial clinical implications and may result in practice changes regarding the extent of thyroid surgery on low-stage pediatric PTC.</p>

<p>Beckwith-Wiedemann syndrome (BWS) is a genetic overgrowth and cancer predisposition syndrome, associated with both benign and malignant adrenal findings. Literature review and an institutional case series elucidate the wide spectrum of adrenal findings in BWS patients. The altered expression of the 11p15 region is likely related to adrenal gland hyperplasia and growth dysregulation. Given the absence of guidelines for managing adrenal findings in BWS, we propose a systematic approach to adrenal findings in BWS patients, to allow for maximum detection of potentially malignant pathology without posing additional risk to patients.</p>