Papillary microcarcinoma in comparison with larger papillary thyroid carcinoma in BRAF(V600E) mutation, clinicopathological features, and immunohistochemical findings.
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.
Park
Young Joo
YJ
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Kim
Young A
YA
Lee
You Jin
YJ
Kim
Soon Hui
SH
Park
So Yeon
SY
Kim
Kyung Won
KW
Chung
June Key
JK
Youn
Yeo Kyu
YK
Kim
Kwang Hyun
KH
Park
Do Joon
DJ
Cho
Bo Youn
BY
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*
D005819:Genetic Markers; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf