伴横纹肌样特征的甲状腺未分化癌临床病理观察

Anaplastic carcinoma of the thyroid with rhabdoid phenotype:a clinicopathologic study of one case

目的探讨伴横纹肌样特征的甲状腺癌的临床病理特点。方法对1例伴横纹肌样特征的甲状腺未分化癌进行组织学、免疫表型检测和超微结构观察,并复习相关文献。结果患者女性,55岁。甲状腺右叶肿块迅速增大,并突破包膜,侵犯肌肉组织、上纵隔、气管及食管。镜下瘤细胞散在分布,黏附性差,呈类圆形,胞质丰富,胞质内见红染均质包涵体,核泡状、偏位,核仁突出,核分裂象可见。横纹肌样瘤细胞vimentin和CAM5.2(+),Ki-67指数80%。电镜示瘤细胞核类圆形,核仁明显,胞质内见不规则成簇分布的中间丝。患者术后6个月死亡。结论甲状腺未分化癌伴横纹肌样特征是罕见的高度恶性肿瘤,主要应与大细胞淋巴瘤、恶性黑色素瘤、生殖细胞瘤等相鉴别,特征性的组织形态及免疫组化标记有助于鉴别诊断。

Objective To study the clinicopathologic features of anaplastic carcinoma of the thyroid with rhabdoid features.Methods One case of anaplastic thyroid carcinoma with rhabdoid features was studied by histology,immunohistochemistry and ultrastructure,and review of relevant literatures.Results A 55-year-old woman complained of a rapidly growing mass within the right lobe of the thyroid.The tumors spread beyond the capsule and extended into the deep muscles,mediastinum superior,trachea and esophagus.Histologically,the tumors were consisted of loosely cohesive rhabdoid cells,which were round to oval in shape and characterized by abundant cytoplasm containing eosinophilic hyaline inclusions with eccentric,vesicular nuclei,prominent nucleoli and mitoses.Immunohistochemically,the rhabdoid cells were positive for vimentin and CAM5.2.The Ki-67 labeling index of the rhabdoid component was high.The patient died 6 months later.Conclusions Thyroid undifferentiated carcinoma with rhabdoid features is rare with highly aggressive behavior.Its diagnosis was established on the characteristic morphological features and immunohistochemical findings and may be confused with some malignant tumors mainly including large cell lymphoma,malignant melanoma and germinoma.