摘要目的:探讨SMARCB1（INI1）缺失的鼻腔鼻窦癌临床病理特征及其诊断和鉴别诊断。方法:收集2016至2018年复旦大学附属眼耳鼻喉科医院手术切除SMARCB1（INI1）缺失的鼻腔鼻窦癌标本/活检病例6例，观察其临床特点、影像学特征、组织形态、免疫组织化学特征以及预后，并结合文献进行复习。结果:5例男性，1例女性；年龄37~75岁（平均约56岁）。1例患者属于T2期，5例患者属于T4期，CT及MRI示鼻腔鼻窦占位伴骨质破坏。镜下观察：肿瘤境界不清，基底样细胞型4例，肿瘤细胞形态较单一，高核质比，细胞质稀少，呈巢状或片状分布于间质中；横纹肌样细胞型2例，肿瘤细胞呈巢状或条索状排列，细胞胞质丰富，嗜酸性，核偏位。免疫组织化学染色示6/6 INI1完全缺失，6/6弥漫强阳性表达广谱细胞角蛋白（CKpan），6/6均不表达S-100蛋白，6/6 EB病毒编码的小RNA（EBER）原位杂交阴性，4/6部分表达p63，1/5部分表达突触素，1/5部分表达p16，Ki-67阳性指数范围30%~70%。5例患者随访1~26个月，其中1例因广泛转移死亡，1例复发，2例淋巴结转移，1例无复发和转移。1例失访。结论:SMARCB1（INI1）缺失的鼻腔鼻窦癌恶性程度高，病程进展快，预后差，组织形态主要为基底样细胞型和横纹肌样细胞型，细胞核INI1完全缺失有助于诊断及鉴别诊断。

abstractsObjective:To study the clinicopathological features, diagnostic features and differential diagnoses of SMARCB1 (INI1)-deficient sinonasal carcinoma (SDSC).Methods:Six cases of SDSC diagnosed at Eye, Ear, Nose and Throat Hospital, Fudan University from 2016 to 2018 were retrieved; the clinical features, histomorphology, immunophenotype, radiology and outcome were analyzed with review of literature.Results:There were five men and one woman with age range of 37 years to 75 years (mean 56 years). One case was in stage T2, and 5 cases were in stage T4. Computer tomography and magnetic resonance imaging showed a mass occupying the sinonasal cavity with bone destruction in all six patients. Microscopically, the tumors had infiltrative margins. Four tumors were composed mostly of basaloid cells, which possessed high nuclear/cytoplasmic ratio,scant cytoplasm,and minimalnuclear pleomorphism; and the cells were arranged in sheets or nests in a desmoplastic stroma. Two tumors were composed of rhabdoid cells, which possessed abundant, eosinophilic cytoplasm and eccentric nuclei, often growing in a nests or sheets pattern. Immunohistochemical staining showed that 6/6 cases had complete loss of INI1, diffusely and strongly positive for CKpan, and were negative for S-100 and EBER ISH; 4/6 cases were focally positive for p63; 1/5 was focally positive for Syn and p16. The Ki-67 index was 30% to 70%. The follow-up period ranged 1-26 months, with one patient died of extensive metastases, one had local recurrence, and two had lymph node metastases; one was alive without disease, and one was lost to follow-up.Conclusions:SMARCB1 (INI1)-deficient sinonasal carcinoma is mostly aggressive, with rapid progression and poor prognosis. Histomorphological spectrum predominantly consists of basaloid type and rhabdoid type. The complete loss of nuclear expression of INI1 can help to distinguish this tumor from its many mimickers.