Handra-Luca Adriana
APHP GHU Avicenne, Bobigny, France.
Université Paris Nord Sorbonne Cite, Bobigny, France.
Iran J Pathol. 2018 Spring;13(2):276-280. Epub 2018 Jul 17.
Squamous cell differentiation (SCD) may occur in papillary thyroid carcinoma (PTC) only at metastatic sites. We have studied cytokeratin CK5/6 and P63 along with TTF1 (thyroid transcription factor 1) and B-Raf (V-Raf murine sarcoma viral oncogene homolog B1) immunohistochemical expression in neck lymph node metastases of thyroid PTC showing SCD. The patient (21-years) presented with a neck mass. The check-up revealed bilateral thyroid nodules. Total thyroidectomy and neck lymph node dissection were performed. The diagnosis was that of bilateral PTC with lymph node metastases (pT-1N1Mx). The metastases were peculiar by the presence of cystic change and of SCD. The thyroid PTC expressed P63 focally and, TTF1 and B-Raf diffusely. Cytokeratin 5/6 was expressed only in the lymph node metastases, in the metastatic cyst lining and in the SCD foci. The P63+ cells outnumbered those CK5/6+. TTF1 expression was faint in SCD. Metastatic, both classical PTCand SCD-epithelia expressed B-Raf. The expression patterns of CK5/6, P63, TTF1 suggest a luminal/central-to-abluminal/peripheral direction for SCD development from PTC-epithelia in lymph node metastases. Whether this metaplasia type may reflect a regression to a less aggressive morphotype or a progression-switch to squamous cell carcinoma-type differentiation in a composite tumor remains matter of debate.
鳞状细胞分化（SCD）可能仅在甲状腺乳头状癌（PTC）的转移部位出现。我们研究了细胞角蛋白CK5/6和P63，以及甲状腺转录因子1（TTF1）和B-Raf（V-Raf鼠肉瘤病毒癌基因同源物B1）在显示SCD的甲状腺PTC颈部淋巴结转移灶中的免疫组化表达。该患者（21岁）表现为颈部肿块。检查发现双侧甲状腺结节。行甲状腺全切术和颈部淋巴结清扫术。诊断为双侧PTC伴淋巴结转移（pT-1N1Mx）。转移灶因存在囊性变和SCD而具有特殊性。甲状腺PTC局灶性表达P63，弥漫性表达TTF1和B-Raf。细胞角蛋白5/6仅在淋巴结转移灶、转移囊肿内衬及SCD灶中表达。P63阳性细胞数量多于CK5/6阳性细胞。TTF1在SCD中的表达较弱。转移性的经典PTC和SCD上皮均表达B-Raf。CK5/6、P63、TTF1的表达模式提示在淋巴结转移中，SCD从PTC上皮向管腔/中央至无管腔/外周方向发展。这种化生类型是否可能反映向侵袭性较小的形态学类型的退变，或者在复合肿瘤中向鳞状细胞癌类型分化的进展转换，仍存在争议。
