Argyris Prokopios P, Bilodeau Elizabeth A, Yancoskie Aaron E, Trochesset Denise, Pambuccian Stefan E, Wetzel Stephanie L, Shah Sonal S, Edelman Morris, Freedman Paul, Dolan Michelle, Koutlas Ioannis G
Division of Oral and Maxillofacial Pathology, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
Department of Diagnostic Sciences, University of Pittsburgh School of Dental Medicine, Pittsburgh, PA, USA.
Histopathology. 2016 Oct;69(4):607-13. doi: 10.1111/his.12973. Epub 2016 May 6.
Ectomesenchymal chondromyxoid tumour (ECT) is a rare, benign intraoral neoplasm showing a predilection for the anterior dorsum of the tongue. The World Health Organization includes ECT in the pathological spectrum of soft tissue myoepithelioma. EWS RNA-binding protein 1 gene (EWSR1) rearrangement is found in 45% of cutaneous, soft tissue and bone myoepithelial neoplasms, and pleomorphic adenoma gene 1 (PLAG1) aberrations are found in 37% of EWSR1-negative soft tissue myoepitheliomas. The aim of this study was to evaluate the presence of EWSR1 and PLAG1 rearrangements in ECTs.
Eleven formalin-fixed, paraffin-embedded ECTs were evaluated with fluorescence in-situ hybridization probes for EWSR1 (22q12) and PLAG1 (8q12). Among the 11 ECTs tested, three (27.3%) showed EWSR1 rearrangement in >15% of tumour cells, whereas eight (72.7%) cases did not show EWSR1 rearrangement. Eight of nine (89%) ECTs showed gain of EWSR1, probably representing gain of all or part of chromosome 22, in a varying proportion of neoplastic cells ranging between 1.4% and 27.9%. PLAG1 rearrangement was not detected in the successfully hybridized tissue sections (7/11). No correlation was observed between the molecular and histopathological findings, such as morphology of the neoplastic cells, the presence of atypia, and matrical type.
We identified EWSR1 rearrangement in >25% of ECTs. These results suggest that some ECTs are at least genetically related to myoepithelioma of the soft parts. Finally, PLAG1 aberrations do not appear to be critical in the pathogenesis of ECT of the tongue.
外胚间叶性软骨黏液样肿瘤（ECT）是一种罕见的口腔内良性肿瘤，好发于舌背前部。世界卫生组织将ECT纳入软组织肌上皮瘤的病理范畴。在45%的皮肤、软组织和骨肌上皮性肿瘤中发现了EWS RNA结合蛋白1基因（EWSR1）重排，在37%的EWSR1阴性软组织肌上皮瘤中发现了多形性腺瘤基因1（PLAG1）畸变。本研究的目的是评估ECT中EWSR1和PLAG1重排的情况。
对11例福尔马林固定、石蜡包埋的ECT进行荧光原位杂交检测，使用针对EWSR1（22q12）和PLAG1（8q12）的探针。在检测的11例ECT中，3例（27.3%）在>15%的肿瘤细胞中显示EWSR1重排，而8例（72.7%）未显示EWSR1重排。9例ECT中有8例（89%）在不同比例（1.4%至27.9%）的肿瘤细胞中显示EWSR1增加，可能代表22号染色体全部或部分增加。在成功杂交的组织切片（7/11）中未检测到PLAG1重排。未观察到分子和组织病理学结果之间的相关性，如肿瘤细胞形态、异型性的存在和基质类型。
我们在>25%的ECT中鉴定出EWSR1重排。这些结果表明，一些ECT至少在基因上与软组织肌上皮瘤相关。最后，PLAG1畸变在舌ECT的发病机制中似乎并不关键。
