title: Review of clinical and pathological features of 93 cases of well-differentiated thyroid carcinoma in pediatric age at the Lisbon Centre of the Portuguese Institute of Oncology between 1964 and 2006.
abstract: BACKGROUND
  Thyroid carcinoma is the most common endocrine malignancy. In childhood, thyroid carcinoma usually behaves aggressively and relapses frequently. Nevertheless, it has a favorable prognosis. Our aim is to present our experience with pediatric well-differentiated thyroid carcinoma (WDTC) treated at the Portuguese Institute of Oncology in Lisbon (L-PIO), between 1964 and 2006.
  
  
  METHODS
  Review of clinical files of WDTC in≤18-year-old patients selected from the databases of the Endocrinology Service of L-PIO and the South Portugal Regional Cancer Registry (SPCR).
  
  
  RESULTS
  93 cases of WDTC were found. Of these, 70 (75.3%) were girls. The median age was 15 years old (range 5-18) with a median follow-up time of 15.1 years (range 0.2-47.8). The most common histological diagnosis was papillary carcinoma of the classical variant (n=60, 64.5%). Initial staging showed locoregional dissemination in 27 (29.0%) patients and distant metastasis in 16 (17.2%) patients. Median age was lower in patients with distant disease than in patients with locoregional disease or with disease confined to the thyroid (P=0.007). After the initial treatment, 44 (47.3%) patients were in remission and 46 (49.5%) had persistent disease (lost follow-up in 3). Of the disease-free patients after initial treatment, 11 (25.0%) relapsed later. At the last observation, most patients (n=63, 67.7%) showed no evidence of disease.
  
  
  CONCLUSIONS
  Our study demonstrates that children with distant metastatic disease are younger than children with a less aggressive disease. However, in both groups the response to treatment is favorable and the prognosis is usually excellent.
authors.affiliation: Endocrinology Service, Lisbon Centre of the Portuguese Institute of Oncology, Francisco Gentil, Lisbon, Portugal. Electronic address: mmdsvieira@gmail.com.
authors.forename: Margarida
authors.initials: M
authors.lastname: Silva-Vieira
authors.affiliation: Endocrinology Service, Lisbon Centre of the Portuguese Institute of Oncology, Francisco Gentil, Lisbon, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Santos
authors.affiliation: Endocrinology Service, Lisbon Centre of the Portuguese Institute of Oncology, Francisco Gentil, Lisbon, Portugal; University of Medical Sciences, New University of Lisbon, Portugal.
authors.forename: Valeriano
authors.initials: V
authors.lastname: Leite
authors.affiliation: Endocrinology Service, Lisbon Centre of the Portuguese Institute of Oncology, Francisco Gentil, Lisbon, Portugal.
authors.forename: Edward
authors.initials: E
authors.lastname: Limbert
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D011174:Portugal; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy
keywords: Cancer; Pediatric age; Thyroid