title: Tall cell variant of papillary thyroid microcarcinoma: clinicopathologic features with BRAF(V600E) mutational analysis.
abstract: BACKGROUND
  The tall cell variant of papillary thyroid carcinoma is an aggressive subtype that generally presents as a large tumor in the advanced stage; however, little is known about the tall cell variant of microcarcinoma (tumors measuring <1 cm). In this study, we compare the tall cell variant of microcarcinoma (microTCV) with classic papillary microcarcinomas to examine the hypothesis that, despite the small size, the microTCV may be more aggressive than the classic papillary microcarcinoma.
  
  
  METHODS
  We identified 27 microTCV patients and compared their clinicopathologic features and BRAF(V600E) mutational status with classic papillary microcarcinomas matched by age and size. The patients with microTCV included 22 women and 5 men aged 33 to 74 years (median age, 56 years). All patients underwent total thyroidectomy; 20 patients had lymph node dissection.
  
  
  RESULTS
  Tumor size in microTCV patients ranged from 2 mm to 10 mm (median, 7 mm). Extrathyroidal extension and lymphovascular invasion were seen in 9 (33%) and 4 (15%) tumors, respectively. Thirteen patients (48%) harbored multifocal papillary carcinomas. Metastasis to central compartment lymph nodes was seen in 8 patients and to lateral cervical nodes in 3 patients. Nine of the 25 patients (36%) presented at an advanced stage (stage III/IVA). The BRAF(V600E) mutation was detected in 25 of 27 tumors (92.6%). In contrast, age- and size-matched classic papillary microcarcinomas (n=26) showed no extrathyroidal extension (p=0.002), lymphovascular invasion in 1, central compartment lymph node metastasis in 2, lateral cervical node metastasis in 1, multifocal tumors in 10 (38.5%), the BRAF(V600E) mutation in 20 (76.9%), and it infrequently presented in stage III/IVA (7.7%, p=0.02).
  
  
  CONCLUSIONS
  The microTCV form is associated with aggressive features at presentation, and it should be differentiated from other papillary thyroid microcarcinomas.
authors.affiliation: 1 Department of Pathology, Yale School of Medicine , New Haven, Connecticut.
authors.forename: Jane
authors.initials: J
authors.lastname: Bernstein
authors.forename: Renu K
authors.initials: RK
authors.lastname: Virk
authors.forename: Pei
authors.initials: P
authors.lastname: Hui
authors.forename: Avinash
authors.initials: A
authors.lastname: Prasad
authors.forename: William H
authors.initials: WH
authors.lastname: Westra
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tallini
authors.forename: Adebowale J
authors.initials: AJ
authors.lastname: Adeniran
authors.forename: Robert
authors.initials: R
authors.lastname: Udelsman
authors.forename: Clarence T
authors.initials: CT
authors.lastname: Sasaki
authors.forename: Sanziana A
authors.initials: SA
authors.lastname: Roman
authors.forename: Julie A
authors.initials: JA
authors.lastname: Sosa
authors.forename: Manju L
authors.initials: ML
authors.lastname: Prasad
mesh_terms: D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000235:genetics / Q000473:pathology*; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D048493:Proto-Oncogene Proteins B-raf