伴有核极向倒置的乳头状肾肿瘤4例临床病理分析

Papillary renal neoplasm with reverse polarity:A clinicopathological analysis of 4 cases

目的 探讨伴有核极向倒置的乳头状肾肿瘤(PRNRP)的临床病理特征、免疫表型、分子特征及预后。方法 收集2016年1月至2022年7月本院存档的4例PRNRP的临床病理资料,选取典型蜡块行免疫组化检测,Sanger测序法行K-Ras突变检测,并进行预后分析。结果 男性1例,女性3例,年龄48~79岁,中位年龄70岁。肿瘤最大径1.8~6.0 cm,平均3.95 cm。4例均为右肾,术后病理分期均为pT1。3例既往误诊。镜下肿瘤均具有纤维性假包膜,局部囊性,肿瘤由具有纤维血管轴心的复杂分支乳头状结构构成,乳头轴心伴有透明变性或水肿,表面被覆单层立方或柱状上皮,胞质嗜酸性,细颗粒状,核特征性的排列于远离基底膜的胞质顶端,大小一致,WHO/ISUP 1~2级,未见或极少见核仁。4例免疫组化均弥漫阳性表达PAX8、GATA3、CK7、K903,E-cadherin呈“杯口”状膜阳性,P504s、CD10、vimentin、CA-IX等阴性,Ki-67增殖指数1%~2%。1例经检测证实K-Ras基因(p.G12D)突变。平均随访40个月均无复发及转移。结论 PRNRP是新近被描述的一种少见的乳头状肾肿瘤,具有独特的组织形态、免疫表型及分子特征,生物学行为惰性,应区别于其他肾细胞癌,准确的诊断对于指导恰当的治疗方式和精准的预后判断具有重要意义。

Objective To investigate the clinicopathological features, immunophenotypes, molecular genetic characterization and prognosis of the papillary renal neoplasm with reverse polarity(PRNRP). Methods Clinicopathological data of 4 cases of PRNRP From January 2016 to July 2022 of our department were retrospectively analyzed.Typical paraffin-embedded blocks were obtained for immunohistochemical staining, Sanger sequencing was performed to identify K-Ras mutations, the relevant literatures were reviewed, and prognosis were analyzed. Results There were 1 male and 3 female patients, aged from 48 to 79 years(median: 70 years), the tumor size ranged from 1.8 to 6.0 cm(mean: 3.95 cm). All were right sided and postoperative pathological stage were pT1. Three were initially misdiagnosed. Microscopically, all cases had fibrous pseudocapsules and partially cystic, all tumors were composed of complex branching papillary architecture with a fibrovascular core showed partially hyalinosis or edematous, the surface was covered by a single layer of cuboidal or columnar cells, with granular eosinophilic cytoplasm, the nuclei were monotonous in size and typically located toward the apical surface away from the basement, WHO/ISUP grade 1-2 with no or few nucleoli. Immunohistochemically, all 4 cases showed diffuse positive expression of PAX8, GATA3, CK7, and K903, E-cadherin expression in a “cup-like” staining appearance, and no expression of P504s, CD10, vimentin, or CA-IX, with a Ki-67 index of 1%-2%. K-Ras mutation(p.G12D) was confirmed in one performed case. All patients were alive without metastasis or recurrence during a mean follow-up of 40 months. Conclusion PRNRP is a recently described, rare papillary renal neoplasm with characteristic morphological, immunophenotypic and molecular features, and indolent behaviors. It should be differentiate from other renal cell carcinoma, definitive diagnosis is of great significance for proper treatment choice and accurate prognostication.