摘要目的:探讨原发皮肤鼻型结外NK/T细胞淋巴瘤（pcENKTCL-NT）的临床病理特征及鉴别诊断。方法:收集郑州大学第一附属医院病理科2016年1月至2019年12月间所有确诊为pcENKTCL-NT病例15例，分析其临床资料，并结合形态学、免疫表型、原位杂交及基因检测进行分析。结果:15例患者中，男性7例，女性8例，男女比为1.0∶1.1，年龄29~86岁，中位年龄59.3岁，患者均因皮肤病变入院就诊。皮损表现，可表现皮肤溃疡，散在片状红丘疹，局部伴有水疱；可呈质硬的结节状肿块，部分呈融合性片状红斑；可表现为多个散在大小不等结节，部分皮损类圆形破溃。皮损分布，下肢8例，胸部4例（1例合并上肢病变），躯干2例，颈部1例。多数患者对DDGP联合治疗方案（顺铂、地塞米松、吉西他滨、培门冬酶）敏感。组织学上，多数病变表现肿瘤细胞侵犯表皮，可见皮肤附属器累及，真皮浸润，呈弥漫分布，并有血管及管周破坏，部分可见皮下脂肪组织累及。细胞形态学上，多数为小~中淋巴细胞混合，部分为大细胞、混合细胞或小细胞。免疫组织化学，所有病例瘤细胞表达标记CD3、CD3ε及T细胞胞质内抗原1（TIA-1），不表达CD20及CD8，绝大部分病例表达CD56及颗粒酶B，多数病例不表达CD5，Ki-67阳性指数50%~90%，原位杂交所有病例均检出EB病毒阳性，部分CD56阴性病例发现T细胞受体基因克隆性重排。15例患者（随访5~45个月），其中1例失访，5例患者确诊后于5~13个月内死亡，死亡占比5/14，死亡患者平均生存时间8.6个月。结论:pcENKTCL-NT少见，但侵袭性强，预后差，皮损表现及组织病理形态相对多样，诊断中应结合临床、病理形态、免疫表型及EB病毒原位杂交，必要时结合分子遗传学检测，同时注意与其他相似病变进行鉴别，以免漏诊、误诊。

abstractsObjective:To investigate the clinicopathological features and differential diagnosis of primary cutaneous nasal extranodal NK/T cell lymphoma (pcENKTCL-NT).Methods:Fifteen cases of pcENKTCL-NT were collected at the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2019. The clinical characteristics, morphological features, immunophenotypes, and results of in situ hybridization and gene detection were analyzed.Results:Among the 15 patients, 7 were male and 8 were female, with a male to female ratio of 1.0∶1.1. Their ages ranged from 29 to 86 years, and the median age was 59.3 years. All patients were hospitalized for skin lesions, including skin ulcers, scattered patchy red papules, and local blisters. The skin lesion might be a hard nodular mass, and part of it was a confluent patchy erythema; it could be manifested as multiple scattered nodules of different sizes, and some lesions were like round ulceration. There were 8 cases of lower limbs, 4 cases of chest (1 case with upper limb lesions), 2 cases of trunk and 1 case of neck. Most of the patients were sensitive to GGDP regimen (cisplatin, dexamethasone, gemcitabine and pemostatin). Histologically, most lesions showed tumor cells invading the epidermis and skin appendages, dermal infiltration, diffuse distribution, vascular and peritubular destruction, and some subcutaneous adipose tissue involvement. Morphologically, most of the tumor cells were mixed with small-to medium-size lymphocytes, and some were large cells, mixed cells or small cells. Immunohistochemistry showed that CD3, CD3 ε and TIA-1 were expressed in all cases, but not CD20 and CD8. CD56 and granzyme B were expressed in most of the cases, and CD5 was not expressed. Ki-67 positive index was about 50%-90%. EBV in situ hybridization was positive in all cases. The clonal rearrangement of T cell receptor gene was found in some CD56 negative cases. The 15 patients were followed up for 5-45 months, and one of them was lost to follow-up. Five patients died within 5-13 months after the diagnosis, accounting for 35.7% (5/14) of the 14 patients. The average survival time of the deceased patients was 8.6 months.Conclusions:The incidence rate of pcENKTCL-NT is relatively low, but its biological behavior is aggressive and its prognosis is overall poor. Its skin lesions and histopathological features are relatively diverse. The diagnosis should be determined with using clinical data, histological morphology, immunophenotype and EB virus in situ hybridization. At the same time, attention should be paid to differential diagnosis from other cutaneous lymphoma with cytotoxic phenotype to avoid missed diagnosis and misdiagnosis.