title: Papillary microcarcinoma in comparison with larger papillary thyroid carcinoma in BRAF(V600E) mutation, clinicopathological features, and immunohistochemical findings.
abstract: BACKGROUND
  Papillary thyroid microcarcinoma (PMC; <or=1 cm) is thought to take a benign course during the lifetime. However, recent studies showed high recurrence rates for PMC.
  
  
  METHODS
  We analyzed the clinicopathological features, long-term prognosis, and some molecular characteristics including BRAF(V600E) mutation by retrospectively reviewing the records of 1150 patients with papillary thyroid carcinoma (PTC), 278 with PMC, and 868 with PTC >1 cm.
  
  
  RESULTS
  The prevalence of extrathyroidal invasion (52.2%) and initial nodal metastasis (34.9%) in patients with PMC was surprisingly high and almost as high as that for patients with PTC (72.4% and 51.8%, respectively). The rate of recurrent or persistent disease did not differ between patients with PMC and PTC (recurrent or persistent disease, 6.1% vs 14.1%; 53.4- vs 84.2-month follow-up; n = 98 vs 647; corrected p = .112). The frequency of BRAF(V600E) mutation was similar in patients with PMC and PTC (65.6% vs 67.2%). Immunohistochemical staining showed no different expression pattern according to the tumor size.
  
  
  CONCLUSIONS
  These results suggest that PMC is not an occult cancer and it can act like larger PTC. Therefore, PMC should not be underestimated in practice.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.forename: Young A
authors.initials: YA
authors.lastname: Kim
authors.forename: You Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Soon Hui
authors.initials: SH
authors.lastname: Kim
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Park
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.forename: June Key
authors.initials: JK
authors.lastname: Chung
authors.forename: Yeo Kyu
authors.initials: YK
authors.lastname: Youn
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
mesh_terms: D000328:Adult; D002291:Carcinoma, Papillary / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology*; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D015995:Prevalence; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology*
chemical_list: D005819:Genetic Markers; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf