术前易误诊为恶性肿瘤的肾脏静脉畸形临床病理分析及文献复习

Renal venous malformation easily misdiagnosed as malignant tumor before surgery: a clinicopathological analysis and review of literature

目的 探讨肾脏静脉畸形(venous malformation, VM)的临床病理学特征,避免误诊、漏诊。方法 收集1例肾脏VM患者的临床病理资料,结合相关文献复习,总结其病理形态学特征和鉴别诊断要点。结果 患者女性,68岁,因无痛性肉眼血尿6天就诊,术前及术中均考虑肾脏恶性肿瘤而行肾脏切除术。巨检为肾脏根治性标本,肾脏大小9.2 cm×4.5 cm×4.2 cm,皮髓质分界清,切面近肾盂处见一暗红色囊实性肿块,大小1.5 cm×1.0 cm×0.7 cm,呈海绵状,界欠清,其下方肾盂肾盏黏膜面暗红色。低倍镜下见肿块境界不清,由不规则扩张的畸形脉管腔呈结节状增生伴出血,部分区域与肾窦处脂肪组织穿插生长;中-高倍镜下见畸形血管大小不一,部分内衬单层扁平内皮细胞,管壁厚薄不均,管腔内充血、出血,局部血栓形成伴乳头状血管内皮增生;血管之间以及与脂肪组织交界处可见纤维母/肌纤维母细胞样梭形细胞增生伴出血,细胞形态较一致,无明显异型性及核分裂象。免疫表型:血管壁及增生的梭形细胞表达Vim及SMA,血管腔内及乳头状结构区表达CD31及CD34,均不表达CK、CK7、HCK、P63、PAX-8、CD10、CAIX、Cathepsin K、HMB45、Melan-A及TFE3,增生的梭形细胞区域Ki-67增殖指数5%~10%。弹力纤维染色畸形血管呈阴性。结论 肾脏VM是一种较为罕见的肾脏良性血管性病变,术前诊断困难,易误诊为恶性肿瘤而行根治性肾脏切除术,术后需与富于血管的肾脏良恶性病变或肿瘤鉴别,预后良好。

Objective To investigate the clinicopathological features of renal venous malformation(VM) in order to avoid misdiagnosis. Methods The clinicopathological data of one case of renal VM was collected, as well as its pathomorphological characteristics and differential diagnosis were summarized, and related literatures were reviewed. Results A 68-year old female was treated for painless gross hematuria for 6 days. Renal malignancy was considered before and during operation. Macroscopic examination of radical nephrectomy specimen revealed a dark-red and cystic-solid mass like sponge that measured 1.5 cm × 1.0 cm × 0.7 cm near the renal pelvis with unclear enough boundary. The mucosa of the lower renal pelvis and calyces was dark red. Under low power microscope, the boundary of the mass was unclear. The abnormal vascular lumen with irregular expansion showed nodular hyperplasia with bleeding, mutually interspersing with adipose tissue of renal sinus in some areas;Under medium and high power microscope, the abnormal blood vessels varied in size with uneven thickness of vascular wall, partially lined with single-layer flat endothelial cells. Congestion and bleeding in the vascular cavity, and local thrombosis with local papillary vascular endothelial hyperplasia could be seen. Spindle cells with fibroblastic and myofibroblastic differentiation persented between blood vessels, as well as at the junction with adipose tissue. The morphology of spindle cells was relatively consistent, without obvious atypia and mitosis. Immunophenotypically, vascular wall and proliferative spindle cells showed positivity for vim and SMA, and positive for CD31 and CD34 in vascular lumen and papillary structure area, but negative for CK, CK7, HCK, p63, Pax-8, CD10, CAIX, cathepsin K, HMB45, Melan-A and TFE3. The Ki-67 index was approximately 5%~10% mainly concentrating in the area of proliferative spindle cells. The abnormal blood vessels were negative by elastic fiber staining. Conclusion Renal VM is a rare benign vascular disease of the kidney with good prognosis. It is scarcely possible to make a definite diagnosis before operation. It is easy to be misdiagnosed as malignant tumor, resulting in radical nephrectomy. After operation, a series of benign and malignant renal lesions or tumors with abundant blood vessels need to be differentiated.