后肾腺瘤临床病理学特征观察

Clinical and pathological characteristics of metanephric adenoma

目的探讨后肾腺瘤(metanephric adenoma,MA)的临床病理学、免疫组织化学和分子遗传学特征及预后。方法2017年和2019年2例女性MA临床资料,通过HE及免疫组织化学染色进行形态学观察,运用ARMs-PCR法检测BRAF-V600E基因状态。结果病例1肿瘤大小9.5cm,切面淡棕,实性,质中,部分区域出血;病例2肿瘤大小3.5cm,为穿刺标本。显微镜下肿瘤由均匀一致的小细胞构成,排列成密集腺泡样结构,灶区呈乳头状及肾小球样结构。肿瘤细胞无异型性,细胞质少,核圆形/椭圆形,未见核仁,核分裂未见,间质可见基底膜样物,并见少量砂砾体。免疫组织化学染色示CK7、EMA、S100、CD10、SY阴性,AMACR局灶阳性,WT1、vimentin、CD57和BRAF-V600E阳性,Ki67(3%+);病例1存在BRAF-V600E基因突变。结论后肾腺瘤是一种罕见原发于肾脏的上皮源性肿瘤。术前影像学不易与恶性肿瘤鉴别,病理形态学特征结合免疫组化及分子遗传学结果有助于明确后肾腺瘤的诊断。MA预后良好,但生物学行为及细胞起源不确定,术后需长期随访观察。

Objective To study the clinical and histopathological features,immunohistochemical characteristics,molecular genetic changes and prognosis of metanephric adenoma(MA).Methods The tissue samples were collected from two female MA patients between 2017 and 2019.The tissues were subjected to histological and immunohistochemical examination using HE staining and the EnVision system.The BRAF-V600E genetic mutation was tested using ARMs-PCR.Results Case 1:the tumor size was 9.5cm,with solid change in cross section,light-brown appearance,and partial bleeding areas.Case 2:a puncture specimen and the tumor size was 3.5cm.Microscopically,the tumors were composed of uniform small cells,arranged in dense glandular bubbles.Papillary and glomerular structures could be observed in focal areas.The tumor cell showed no atypia,with minimal cytoplasm and round or oval nuclei.Nucleoli and mitosis could not be observed.Hyaline degeneration and calcification could be seen in the stroma.Immunohistochemical staining showed the tumor cells were negative for CK7,EMA,S100,CD10 and SY,while positive for AMACR(focal),WT1,vimentin and BRAF-V600E.Ki67(3%+),and case 1 showed genetic mutation in BRAF-V600E.Conclusion MA is a kind of rare renal epithelial neoplasm.It is difficult to distinguish MA from renal malignant tumors by preoperative imaging examination.It is helpful for diagnosis to master its clinical,histopathological characteristics and molecular genetics.MA has a good prognosis,but its biological behavior is controversial,so regular follow-ups are still needed.