Clinicopathologic Characteristics of Pediatric Follicular Variant of Papillary Thyroid Carcinoma Subtypes: A Retrospective Cohort Study

Citations Over TimeTop 12% of 2022 papers

Abstract

Introduction: 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. Methods: 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. Results: 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 (p p = 0.02). Conclusions: 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.

Related Papers

• → Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features in Children: An Institutional Experience and Literature Review(2019)20 cited
• Effect of Lowering the Diagnostic Threshold for Encapsulated Follicular Variant of Papillary Thyroid Carcinoma on the Prevalence of Non-invasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features: A Single-institution Experience in Korea(2017)
• → Ultrasound and cytological characteristics of non-invasive follicular thyroid neoplasm with papillary-like nuclear features compared to papillary carcinomas(2020)14 cited
• → Quand, comment et pourquoi réaliser une imagerie des artères des membres inférieurs ?(2004)5 cited
• → Study of variants of papillary carcinoma of Thyroid with a special emphasis on NIFTP (Non-invasive Follicular Thyroid Neoplasm with Papillary like nuclear features)(2021)