浅谈甲状腺未分化癌的病理诊断

Pathological diagnosis of undifferentiated thyroid carcinoma

甲状腺未分化癌是恶性程度最高的肿瘤之一,发病率低,但死亡率却极高,多见于老年女性,表现为迅速增大的颈部肿块,有明显周围组织受累症状,易发生早期转移。甲状腺未分化癌的组织学特点取决于梭形细胞、鳞状或上皮样细胞、巨细胞三种成分的构成,细胞多形性明显,核分裂像多见,表现为肉瘤样、表皮样甚至鳞样形态改变,或其他罕见形态变异型。肿瘤细胞通常表达角蛋白和PAX-8,而甲状腺球蛋白(Tg)及转录因子(TTF-1)阴性。分子遗传学改变主要包括信号转导通路上关键节点的突变、染色体异常以及表观遗传学改变。未分化癌的组织学起源尚未完全明确,普遍认为可能是分化好的甲状腺癌去分化的终末阶段。

Undifferentiated thyroid carcinoma（UTC） is one of the most aggressive malignant tumors with lower morbidity and higher mortality. UTC usually occurs in elderly female patients. Most cases present with a rapidly enlarging neck mass with local compressive symptoms and early metastases. The morphological features depend on admixture of three main histological patterns（spindle, giant and epithelioid cells）with marked pleomorphism and numerous mitoses. It shows sarcomatoid, epithelioid-squamoid or other rare variants changes. Tumor cells are usually immunoreactive for cytokeratin and PAX-8, but negative for thyroglobulin and TTF-1. The genetic changes include mutations of the key-points in signal pathway, aberrations of chromosomal regions, and modifications of epigenetic targets. It is widely accepted that UTC represents a terminal dedifferentiated of well differentiated thyroid carcinoma, although the definite histogenesis is not clear.