Fan C Y, Wang Y X, Hu P Z, Yang S J
Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
Zhonghua Bing Li Xue Za Zhi. 2023 Aug 8;52(8):791-796. doi: 10.3760/cma.j.cn112151-20221112-00950.
To investigate the clinicopathological characteristics of malignant gastrointestinal neuroectodermal tumors (GNET), and to describe their clinical, histological, immunophenotypic, ultrastructural, and molecular features, diagnosis and differential diagnosis. Three cases of malignant GNET were collected at Xijing Hospital of the Fourth Military Medical University, from 2013 to 2022. All patients underwent surgical resection of the tumor. Histological, immunohistochemical (IHC), ultrastructural and molecular genetic analyses were performed, and the patients were followed up for six months, three years and five years. There were two males and one female patients. The tumors were located in the ileum, descending colon, and rectum, respectively. Grossly, the tumors were solid, firm, and poorly circumscribed, measured in size from 2 to 4 cm in greatest dimension, and had a greyish-white cut surface. These tumors were histologically characterized by a sheet-like or nested population of oval to spindled cells or epithelioid cells with weakly eosinophilic or clear cytoplasm, small nucleoli and scattered mitoses. Electron microscopy showed neuroendocrine differentiation, and no evidence of melanogenesis. IHC staining showed that the tumor cells were diffusely positive for S-100 protein, SOX10, CD56, synaptophysin and vimentin. They were negative for melanocytic markers, HMB45 and Melan A. All three cases showed split EWSR1 signals consistent with a chromosomal translocation involving EWSR1. Next-generation sequencing in one case confirmed the presence of EWSR1-ATF1 fusion. These patients were followed up for 6 months, 3 years and 5 years, respectively, and all of them developed possible lung or liver metastases, and one of them died of multiple pulmonary metastases. Malignant GNET has distinctive morphological, IHC, and molecular genetic features and it should be differentiated from other malignancies of the gastrointestinal tract, especially clear cell sarcoma and melanoma.
探讨胃肠道恶性神经外胚层肿瘤（GNET）的临床病理特征，描述其临床、组织学、免疫表型、超微结构及分子特征、诊断及鉴别诊断。收集第四军医大学西京医院2013年至2022年期间的3例恶性GNET病例。所有患者均接受了肿瘤手术切除。进行了组织学、免疫组织化学（IHC）、超微结构及分子遗传学分析，并对患者进行了6个月、3年及5年的随访。患者2例男性，1例女性。肿瘤分别位于回肠、降结肠和直肠。大体上，肿瘤质地硬实，边界不清，最大径为2至4 cm，切面灰白色。这些肿瘤在组织学上的特征为呈片状或巢状排列的椭圆形至梭形细胞或上皮样细胞，细胞质弱嗜酸性或透明，核仁小，有散在核分裂象。电子显微镜检查显示神经内分泌分化，无黑色素生成证据。IHC染色显示肿瘤细胞S-100蛋白、SOX10、CD56、突触素和波形蛋白弥漫性阳性。黑色素细胞标志物HMB45和Melan A阴性。3例均显示与涉及EWSR1的染色体易位一致的EWSR1信号分裂。1例的二代测序证实存在EWSR1-ATF1融合。这些患者分别随访了6个月、3年及5年，均发生了可能的肺或肝转移，其中1例死于多发肺转移。恶性GNET具有独特的形态学、IHC及分子遗传学特征，应与胃肠道其他恶性肿瘤，尤其是透明细胞肉瘤和黑色素瘤相鉴别。
