双表型鼻腔鼻窦肉瘤8例临床病理分析

Biphenotypic sinonasal sarcoma:a clinicopathologic analysis of eight cases

目的探讨双表型鼻腔鼻窦肉瘤(biphenotypic sinonasal sarcoma,BSNS)的临床病理特征、诊断、鉴别诊断。方法回顾性分析8例BSNS的临床病理、免疫表型特点,其中5例采用荧光原位杂交(fluorescence in situ hybridization,FISH)技术检测Pax-3基因分离情况。结果8例BSNS中男性3例,女性5例;发病年龄26~74岁,中位年龄58岁。临床多表现为鼻塞、鼻出血、眼痛及面部肿胀等。眼观:肿瘤灰白色桑葚样。镜检:形态较一致的梭形细胞在黏膜上皮下呈浸润性生长,并牵拉表面上皮致上皮内陷,近上皮处细胞较密集;肿瘤细胞排列呈束状、鱼骨状,可侵犯骨组织;细胞核呈波浪状,胞质嗜伊红,坏死及核分裂象不明显。间质内可见血管外皮瘤样结构,伴有胶原变性。免疫表型:肿瘤细胞S-100(8/8)、Calponin(8/8)、MSA(7/8)、SMA(7/8)、FXⅢa(8/8)均阳性;Ki-67增殖指数较低(2%~5%)。5例Pax-3分离探针检测均呈阳性,支持BSNS的诊断。所有病例均获得随访,随访时间8~31个月,2例术后复发,6例未见复发。结论BSNS是一种具有神经及肌源性分化特征的低度恶性软组织肉瘤,并伴有Pax-3基因重排,结合形态、免疫表型及分子学改变可明确诊断。

Purpose To investigate the clinicopathologic features,diagnosis,and differential diagnosis of biphenotypic sinonasal sarcoma(BSNS).Methods Eight cases of BSNS were retrospectively studied.The clinicopathologic features,immunohistochemical findings and Results of split signals for Pax-3 gene with FISH were analyzed.Results There were 3 males and 5 females in the 8 cases,with a median age of 58 years(range from 26 to 74 years).Clinically,the patients were characterized by nasal obstruction,epistaxis and facial swelling,as well as eyes ache.Macroscopically,the section of BSNS was grey and resembled a mulberry.Histologically,BSNS with eosinophilic cytoplasm,was characterized by a cellular submucal spindle-cell proliferation,composed of elongated spindle cells arranged in medium to long intersecting fascicles creating a herringbone architecture often with involvement of adjacent bone.The nuclei may be wavy or focally buckled,reminiscent of the cytologic features of Schwann cells.Necrosis was exceedingly rare and mitotic figures were often difficult to identify.The background stroma sometime contained foci of prominent vasculature,which may be“hemangiopericytoma-like,”and occasional foci of wispy,delicate collagen.Immunohistochemically,the tumor cells were positive for S-100(8/8),calponin(8/8),MSA(7/8),SMA(7/8)and FXⅢa(8/8)in some areas and negative for others.The Ki-67 value index of all cases was low(2%-5%).Five cases had split signals for the Pax-3 gene.8 patients,of those 2 patients with recurrence,were available with the follow-up data and the follow-up time was 8 to 31 months.Conclusion Biphenotypic sinonasal sarcoma is a low-grade malignancy harboring Pax-3 rearrangements showing both neural and myogenic features.Although the differential diagnosis of BSNS is broad,careful morphologic inspection together with targeted ancillary studies is often sufficient to arrive at the correct diagnosis.