Noninvasive encapsulated follicular variant of papillary thyroid carcinoma: Should it also be reclassified in children?

Rachel A. Mariani, Rachel Kadakia, Nicoleta C. Arva*

*Corresponding author for this work

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Background: Noninvasive encapsulated follicular variant of papillary thyroid carcinoma (noniEFVPTC) has low risk of adverse outcome in adults, warranting reclassification as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). In children, thyroid nodules have higher risk of malignancy and it is unknown if encapsulated FVPTC (EFVPTC) and infiltrative FVPTC (IFVPTC) tumors have different behavior. We analyzed the clinicopathologic features of follicular variant of papillary thyroid carcinoma (FVPTC) subtypes in our pediatric population to determine if noniEFVPTC has an indolent course as reported in adults. Procedure: We retrospectively studied all patients diagnosed with FVPTC at our institution. The clinicopathologic characteristics of the histologic subtypes were compared. Results: Eighteen patients were identified, all treated with total thyroidectomy. No significant differences in age, sex, tumor size, focality, or prior malignancy were detected between subtypes. Extrathyroidal extension had significantly higher incidence in IFVPTC (5/8) compared with EFVPTC (1/10, P = 0.03), translating in significantly more T3 tumors within IFVPTC subtype (5/8), whereas most EFVPTC cases had T1 staging (6/10, T1 vs. T3, P = 0.05). EFVPTC had significantly lower rate of lymph node involvement (N1 in 2/8) compared with IFVPTC (N1 in 8/8, P = 0.003). Only one patient diagnosed with IFVPTC developed extranodal recurrence. When noniEFVPTC and iEFVPTC were separately compared, the noninvasive form showed no propensity for invasive growth (T3 staging: 0/4 vs. 2/6), lymph node metastasis (N1: 0/3 vs. 2/5) or extranodal recurrence. Conclusion: In children, noniEFVPTC/NIFTP has indolent behavior, warranting consideration of less aggressive management, similar to adults.

Original languageEnglish (US)
Article numbere26966
JournalPediatric Blood and Cancer
Volume65
Issue number6
DOIs
StatePublished - Jun 1 2018

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Keywords

  • encapsulated
  • follicular
  • infiltrative
  • invasive
  • papillary thyroid carcinoma

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Hematology
  • Oncology

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