Casco Fernando, Illanes Moreno Matilde, González Cámpora Ricardo, Moreno Ana, Galera Ruiz Hugo
Department of Anatomic Pathology, Hospital Universitario Reina Sofía de Córdoba, Córdoba, Spain.
Anal Quant Cytol Histol. 2010 Feb;32(1):53-7.
The spindle epithelial tumor with thymuslike differentiation (SETTLE) is a rare thyroid tumor believed to be derived from ectopic thymus tissue or the embryonic remnants of branchial pouches, which displays primitive thymic differentiation. Histologic observation of spindle cells may lead to confusion with other tumors the development and prognosis of which are very different. Differential diagnosis using histochemical markers is essential since although there is a tendency to develop blood-borne metastases, tumor growth is slow and the survival rate in patients followed up is as high as 70%. It mainly affects children and young adults (mean age 15), although cases have been reported in patients ranging from 2 to 59.
A 2-year-old boy presented with a tumor on the anteroinferior aspect of the neck, which had been growing since birth, suggesting a congenital origin. Histologic examination showed spindle cell nodules separated by fibrous bands containing mucous glands and cysts filled with mucoid material. Immunohistochemical markers revealed primitive differentiation; tumor cells stained positive for cytokeratin and vimentin but negative for markers indicative of greater differentiation, such as calcitonin, chromogranin, calretinin, synaptophysin and S-100 protein.
This is the first reported case of SETTLE in the youngest patient which had been growing since birth.
具有胸腺样分化的梭形上皮肿瘤（SETTLE）是一种罕见的甲状腺肿瘤，被认为起源于异位胸腺组织或鳃囊的胚胎残余物，表现出原始胸腺分化。梭形细胞的组织学观察可能会与其他肿瘤混淆，而这些肿瘤的发展和预后差异很大。使用组织化学标记物进行鉴别诊断至关重要，因为尽管该肿瘤有发生血行转移的倾向，但其生长缓慢，随访患者的生存率高达70%。它主要影响儿童和年轻人（平均年龄15岁），不过也有2至59岁患者的病例报道。
一名2岁男孩颈部前下方出现一个肿瘤，自出生以来一直在生长，提示先天性起源。组织学检查显示梭形细胞结节被含有黏液腺的纤维带和充满黏液样物质的囊肿分隔。免疫组织化学标记物显示为原始分化；肿瘤细胞细胞角蛋白和波形蛋白染色呈阳性，但降钙素、嗜铬粒蛋白、钙视网膜蛋白、突触素和S-100蛋白等提示更高分化的标记物染色呈阴性。
这是首例报道的自出生以来一直在生长的最年轻SETTLE患者病例。
