title: Papillary thyroid carcinomas in patients under 21 years of age: clinical and histologic characteristics of tumors ≤10 mm.
abstract: OBJECTIVE
  To compare clinical and histologic characteristics of papillary thyroid carcinomas (PTCs) ≤10 mm in patients ≤21 years old with larger ones and with microcarcinomas in adults.
  
  
  METHODS
  Retrospective study of patients with PTC diagnosed between 1983 and 2012. Medical records were reviewed and information about age, sex, tumor size, intra/extrathyroid extension, lymph node, and distant metastases were collected.
  
  
  RESULTS
  Patients ≤21 years old (n = 93) and adults (n = 1235) with PTC were identified. Among the former, 34 had PTC ≤10 mm (37.4%) and among the latter, 584 had papillary thyroid microcarcinoma (PTM) (47.3%), P = .082. Patients with tumors ≤10 mm less frequently had extrathyroidal extension and lymph node metastases compared with larger tumors (8.8% vs 33.3%, P = .017, and 60.0% vs 95.2%, P = .001, respectively). The percentage of PTC ≤10 mm increased with age (7.1%, 32.0%, and 48.1% in age groups ≤15, 15-18, and >18 to ≤21 years old, respectively; P = .016). Mean tumor size was larger (6.8 ± 2.7 vs 5.8 ± 2.8 mm, P = .030), and lymph nodes metastases were more frequent (41.2% vs 18.6%, P = .003) in patients ≤21 years of age compared with adults with PTM. The frequency of multifocal cancers decreased between 1983-1992, 1993-2002, and 2003-2012 (66.7%, 53.6%, and 27.1%, respectively, P = .019).
  
  
  CONCLUSIONS
  The frequency of PTC ≤10 mm is low in children, increases in adolescents, and reaches that of adults at 18-21 years of age. Mean tumor size is larger and metastases to regional lymph nodes more frequent in comparison with PTM in adults. Whether their treatment and follow-up could be based on guidelines used for PTM in adults is questionable.
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece. Electronic address: kpazaitou@in.gr.
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Pazaitou-Panayiotou
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Paschalia K
authors.initials: PK
authors.lastname: Iliadou
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Stylianos
authors.initials: S
authors.lastname: Mandanas
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Theofanis
authors.initials: T
authors.lastname: Vasileiadis
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Periklis
authors.initials: P
authors.lastname: Mitsakis
authors.affiliation: Department of Endocrinology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Tziomalos
authors.affiliation: Endocrine Unit, Department of Medical Therapeutics, Athens University School of Medicine, Thessaloniki, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Alevizaki
authors.affiliation: Department of Pathology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Frideriki
authors.initials: F
authors.lastname: Patakiouta
mesh_terms: D000293:Adolescent; D000328:Adult; D002277:Carcinoma / Q000473:pathology* / Q000556:secondary; D002291:Carcinoma, Papillary / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000556:secondary; D047368:Tumor Burden; D055815:Young Adult