鼻腔鼻窦腺泡状横纹肌肉瘤10例临床病理分析

Sinonasal tract alveolar rhabdomyosarcoma:a clinicopathologic analysis of ten cases

目的探讨鼻腔鼻窦腺泡状横纹肌肉瘤(sinonasal tract alveolar rhabdomyosarcoma,SNT-ARMS)的临床表现、组织学形态、免疫表型及分子遗传学特征、诊断及预后。方法收集10例SNT-ARMS的临床病理资料,行HE及免疫组化EnVision法染色。应用FISH法检测FOXO1基因断裂重组情况,并复习相关文献。结果眼观:临床送检为息肉样病变,切面灰白、灰红色,质嫩。镜检:肿瘤由幼稚的小蓝圆细胞组成,呈巢状分布,瘤巢之间可见纤细的纤维血管间隔,局灶瘤巢中央的瘤细胞变性、脱落,形成特征性的腺泡状结构;部分病例肿瘤细胞呈弥漫实性片状分布。肿瘤细胞形态一致,核染色质粗,可见细小核仁,核分裂活跃;肿瘤胞质分化不明显,少数病例部分细胞含有丰富的透明状胞质。部分病例肿瘤内可见数量不等的花环状多核巨细胞及横纹肌母细胞分化。免疫表型:表达横纹肌免疫组化标志物desmin、Myogenin和(或)MyoD1,部分病例表达CKpan、CK-L、Syn、CD56、ALKp80,不表达CK5/6、CgA、NSE、NeuN、NF、S-100、CD99、CD34、CD20、CD3、Tdt等,Ki-67增殖指数为50%~80%。FISH法检测均显示FOXO1基因断裂重组。结论SNT-ARMS需与其它类型的小蓝圆细胞肿瘤进行鉴别,部分肿瘤表达上皮、神经内分泌标志物,易误诊为低分化癌或神经内分泌癌。

Purpose To investigate the clinical manifestation,histopathology,immunohistochemical,genetic characteristics,differential diagnosis and prognosis of sinonasal tract alveolar rhabdomyosarcoma(SNT-ARMS).Methods The clinical and pathological data of 10 cases SNT-ARMS were enrolled.HE sections and immunohistochemical EnVision staining results were observed under light microscope,and the status of FOXO1 gene translocation was detected by fluorescence in situ hybridization(FISH),and related literatures were also reviewed.Results The tumours were polypoid lesions,and had a flesh consistency with gray white cut surface.The tumors were composed of small round cell nests that were attached to connective tissue septa,in the form of partial cell detachment from these septa,giving the tumour its classic alveolar appearance.Some tumor cells were distributed in a diffuse solid pattern.The tumor cells were monomorphic with round nuclei with coarse chromatin and small nucleoli.The mitotic activity was brisk.The cytoplasm of tumor cells was not obvious,but some cells in a few cases contained abundant pale-staining and clear cytoplasm.Wreath-like multinucleated giant cells and rhabdomyoblasts were seen in a subset of cases.Immunophenotypically,tumor cells were positive for desmin,Myogenin and/or MyoD1,and some cases also expressed CKpan,CK-L,Syn,CD56 and ALKp80.The tumor cells did not express CK5/6,CgA,NSE,NeuN,NF,S-100,CD99,CD34,CD20,CD3,Tdt,etc.The Ki-67 index of tumor cells were 50%-80%.The FOXO1 gene translocation detection was performed by FISH with positive results.Conclusion SNT-ARMS is rare and needs to be differentiated from various other types of small round blue tumors,some tumors express epithelial,neuroendocrine markers,which can lead to their misdiagnosis as poorly differentiated carcinoma or neuroendocrine carcinoma.