Abstract: Background Mesenchymal malignancies prefer hematogenous spread, while epithelial malignancies tend to prefer lymphatic spread. However, mesenchymal malignancies occasionally generate lymphatic metastases. Objective To investigate the clinicopathological features of the epithelioid malignant peripheral nerve sheath tumor (EMPNST). Methods The clinical data, histopathological, histochemical and immunohistochemical features in one case of EMPNST with lymph node metastases were retrospectively analyzed, and the related literatures were reviewed. Results A 42-year-old woman presented right upper arm and shoulder numbness with a right axillary nodule measuring 4 cm × 4 cm × 3 cm for 2 months. Type-B ultrasonic examination showed substantive lesions in right axillary which appeared to be a neurofibroma. CT scan showed soft tissue masses in right axillary with multiple enlarged lymph nodes were considered to be malignant lesions. MR image showed nodules in right armpit muscles were considered to be malignant tumor. The multiple nodules were identified in right axillary and the largest one was about 5 cm × 3 cm × 3 cm intraoperatively. The section of specimen was hard, gray-red and sallow in color with focal necrosis. The nodules were partly circumvoluted with blood vessel and without distinct border. The surrounding nerves were not obviously compressed. Microscopically, the structure of lymph node was damaged. The tumor invaded the surrounding fibrous connective tissue and adipose tissue with focal hemorrhage and necrosis. Tumor cells arranged in sheets, nests, and were separated by thin fibrous and blood vessels tissue. Most tumor cells were epithelioid. They were large in size with abundant cytoplasm. Cell border was indistinct, and the cytoplasm consisted of fine granules. Nuclei were invariably intensely hyperchromatic with coarse chromatin, and were vacuolated with prominent nucleoli in the center of the nuclei. Tumor cells showed frequent mitotic activity. Multinucleated giant cells and interstitial mucous degeneration were presented. Immunohistochemical staining showed that tumor cells were positive for S-100 protein, strong nuclear reactivity for Sox-10, and were positive for vimentin and Col-Ⅳ, and were negative for CK, CEA, EMA, Melan-A, CD56, CD3 and CD20. P53 positive revealed by 40% nuclear of tumor cells. Ki-67 labeling index was above 90%. Histochemical staining showed that the tumor cells were surrounded by reticular fibers. The patient had a medical history which recorded a tumor at the right wrist was removed in other hospital 8 years ago, and the wrist tumor recurred 5 years ago. The pathological diagnosis of the recurred wrist tumor was EMPNST with focal hemorrhage and necrosis. According to the history and the final pathological diagnosis, axillary tumor was diagnosed as lymph node metastasis of EMPNST in right axillary. Conclusion The metastasis of MPNST is mostly through the blood channel. This is the first case of the lymph node metastasis of EMPNST. In clinical work, it should be differentiated from other tumors with similar histopathology.

Key words: Neurilemmoma, Axilla, Lymphatic metastasis, Wrist, Pathology, Immunohistochemistry

摘要： 研究背景 间叶性恶性肿瘤的转移途径以血行转移为主，而上皮性恶性肿瘤大多循淋巴管道转移，但间叶性肉瘤有时也会经淋巴管道进行转移。目的 探讨上皮样恶性外周神经鞘膜瘤的临床病理学特征。方法复习1 例淋巴管道转移性上皮样恶性外周神经鞘膜瘤患者临床资料，通过组织学观察、组织化学染色和免疫组织化学染色研究分析肿瘤细胞特点，并进行文献回顾。结果 患者女性，42 岁。临床表现为右侧腋窝4 cm × 4 cm × 3 cm 大小肿块伴右上臂及肩部麻木。术前影像学检查显示右侧腋窝软组织肿块影及周围多发肿大淋巴结影，考虑恶性病变。术中可见右侧腋窝多个结节状肿块，最大者约5 cm × 3 cm × 3 cm 大小，剖面呈灰红、灰黄色，质地坚硬，局部坏死。显微镜下观察淋巴结结构破坏，肿瘤细胞呈片状或巢状排列，可见纤细的血管纤维组织分隔，大多数肿瘤细胞呈上皮样，可见多核瘤巨细胞，核分裂象易见，部分区域间质呈黏液样变性。肿瘤细胞S-100 蛋白、Sox-10 蛋白、波形蛋白、Col-Ⅳ表达阳性；40%的肿瘤细胞胞核P53 表达阳性；细胞角蛋白、癌胚抗原、上皮膜抗原表达阴性；Ki-67 抗原标记指数> 90%；网状纤维染色显示网状纤维包绕上皮细胞巢。既往曾因“右腕部肿物”行两次“肿物切除术”，术后病理报告为上皮样恶性外周神经鞘膜瘤伴出血及灶性坏死，结合病史，最终诊断为右侧腋窝淋巴结转移性上皮样恶性外周神经鞘膜瘤。结论 上皮样恶性外周神经鞘膜瘤主要通过血行转移，较少发生淋巴管道转移，应注意与具有相似组织学形态的肿瘤相鉴别，以免误诊或漏诊。

关键词: 神经鞘瘤, 腋, 淋巴转移, 腕, 病理学, 免疫组织化学