原发性肾滑膜肉瘤的临床病理观察

Synovial sarcoma of kidney:a clinicopathologic study of 2 cases

目的:探讨原发性肾滑膜肉瘤的临床病理学特征和鉴别诊断。方法:回顾分析2例原发性肾滑膜肉瘤患者的临床表现、组织学特点、免疫表型和分子遗传学改变及随访情况。结果:2例肾滑膜肉瘤患者分别为25岁女性和27岁男性,临床表现为腹痛,肿瘤平均长径为8 cm,呈灰白色均质状肿块伴出血、坏死;显微镜下,肿瘤组织由相对一致的梭形和圆形上皮样细胞呈交错状、片状分布构成,并可见血管外皮瘤样区域,显示为疏密相间的梭形细胞伴分支状薄壁血管。瘤细胞间边界不清,细胞质少至中等,细胞核呈空泡状,伴有小核仁,核分裂象易见。1例可见似肾母细胞瘤中的始基样成分,为边界较清、结节状排列、圆至卵圆形细胞团。免疫组化表达上皮膜抗原(EMA)、CK、CD99、BCL-2、波形蛋白(vimentin),不表达CD34、S-100、SMA、MyoD-1、WT-1、CD10、HMB45。原位荧光杂交SYT双色分离探针标记均见SYT基因重排阳性。随访结果显示,1例患者于术后23个月腹腔内肿瘤复发,另1例患者术后10个月仍无瘤生存。结论:原发性肾滑膜肉瘤罕见,易发生于年轻成人,形态表现与一些肾脏儿科肿瘤、间叶性肿瘤和肾细胞癌有交错;充分取材并进行免疫组化染色及融合基因检测可作出明确诊断。

Objective To study the clinicopathologic features and differential diagnosis of synovial sarcoma of kidney.Methods The clinical,pathological,immunohistochemical and molecular findings,and follow-up data of 2 cases of renal synovial sarcoma were reviewed and analyzed.Results The 2 patients of renal synovial sarcoma were a 25-year female and a 27-year male,presented with abdomen pain.The tumor was 8 cm on average,gray-white and homogeneous with hemorrhage and necrosis.Microscopically,it was composed of uniform spindle and round cells in fascicle and sheet arrangement.Hemangiopericytoma-like area showing alternative hypercellular and hypocellular pattern of spindle cells with thin-walled branching vessels was noted.Tumor cells displayed indistinct border,scanty to moderate cytoplasm,vesicular nuclei with small nucleoli and easily seen mitoses.Blastemic-like pattern showing round to oval cells arranged in distinct nodule liking that found in nephroblastoma was noted in 1 case.Immunohistochemmically,EMA,CK,CD99,BCL-2,vimentin were positive,while CD34,S-100,SMA,MyoD-1,WT-1,CD10,HMB45 were negative.The SYT gene rearrangement was positive when evaluated by fluorescence in situ hybridization using a break-apart probe.Follow-up data revealed recurrence occurred 23 months after surgery in one case,and no evidence of recurrence was seen in another case for 10 months.Conclusions Synovial sarcoma of kidney is rare,usually occurs in young adults,and presents morphological similarity with some pediatric and mesenchymal neoplasm of kidney and renal cell carcinoma.Enough sampling,immunohistochemical staining,fusion gene detection are helpful to make a definite diagnosis.