超声造影对肝脏小占位病变的诊断价值

目的分析较小肝脏占位性病变（直径≤3cm）超声造影表现,探讨超声造影对肝脏小占位病变的诊断价值。方法回顾性分析136例患者156个直径≤3cm的肝脏占位性病变常规超声及超声造影表现,其中恶性病灶74个,良性病灶82个。利用TIC软件分析除外术后瘢痕、坏死结节及性质待定的病灶外的142个病灶造影剂灌注模式,并与病理结果进行对照研究。结果74个恶性病灶及除坏死结节、术后瘢痕外的72个良性病灶不同程度增强。动脉相原发性肝细胞癌（HCC）100%（49/49）增强,其中71.43%（35/49）呈整体增强;实质相85.71%（42/49）呈典型的＂黑洞＂征。转移性肝癌动脉相特征性地表现为厚环状增强者占52.00%（13/25）;实质相88.00%（22/25）呈＂黑洞＂征。良性病变中动脉相后期呈整体增强、斑片状增强及环状增强者分别为48.61%（35/72）、18.06%（13/72）、33.33%（24/72）;实质相呈＂黑洞＂征、强度低于、近似于周围肝组织者分别为1.39%、30.56%、68.06%。肝血管平滑肌脂肪瘤和炎性假瘤造影呈快进快退,类似于恶性肿瘤。TIC分析良性病灶始增时间、增强时间及达峰时间均晚于恶性病灶,差异具有显著性,峰值强度在两组之间无显著性差异。HCC和转移性HCC上述参数无差异。血管平滑肌脂肪和炎性假瘤TIC上述各参数低于良性组其余病变。结论超声造影对提高肝脏小占位病变的定性诊断率有重要的价值,部分良性病变造影表现缺乏特异性,确诊仍须结合其他影像学方法或穿刺活检。     

超声造影在肝占位性病变穿刺活检中的应用

目的探讨超声造影在经皮肝占位性病变穿刺活检中的应用。方法对32例常规超声检查诊断的肝占位性病变进行超声造影,根据病灶内微灌注情况,对其中31例进行常规超声引导下穿刺活检,穿刺标本送病理科行组织学检查。取材量满足病理诊断为取材成功。结果常规超声检查提示32例肝占位性病变病灶内坏死、液化3例,超声造影提示病灶内坏死、液化10例;肝多发占位病灶4例,其中1例（2个病灶）1灶造影剂呈＂快进快出＂,另1灶造影三期与肝实质呈同步等增强,其余3例多发病灶超声造影均呈＂快进快出＂;6例常规超声检查病灶未显示血流,5例超声造影检查有不同程度增强,1例病灶三期均呈无增强,考虑局灶性坏死结节未行穿刺活检。31例肝占位性病变于超声造影动脉期增强区取材,平均穿刺2.13次（66/31）,取材成功率100%（31/31）,确诊率96.80%（30/31）。结论超声造影可敏感地反映肝占位病变微灌注情况,准确分辨肝占位病变坏死、液化区,初步判断病变的良、恶性,指导常规超声准确进行定位取材,在肝占位病变穿刺活检中有重要的临床价值。     

623例膀胱镜活检病理分析

目的 分析因膀胱病变行膀胱镜活检患者的病理类型构成,探讨膀胱镜检查的临床价值.方法 复习我院623例膀胱病变患者经膀胱镜活检组织病理资料.结果 良性肿瘤76例,占12.2%,均为尿路上皮乳头状瘤.恶性肿瘤291例,占46.7%,其中尿路上皮癌254例,腺癌17例,鳞癌6例,转移癌13例,横纹肌肉瘤1例.膀胱黏膜慢性炎症140例,上皮增生50例,分别占22.5%、8.0%;而腺性膀胱炎55例,正常膀胱黏膜8例,前列腺组织3例.结论 尿路上皮性肿瘤仍是最常见的膀胱疾病,其次是膀胱炎性病变.膀胱恶性肿瘤以尿路上皮癌最常见,膀胱腺癌、鳞癌或转移癌等比较少见.膀胱镜活检安全、简便,具有重要的临床应用价值.     

膀胱尿路上皮乳头状瘤32例临床病理特征分析

目的：探讨新发膀胱尿路上皮乳头状瘤的临床病理学特征及其复发、演进的风险。方法：回顾性分析根据1998年WHO／ISUP分类标准诊断出的32例膀胱尿路上皮乳头状瘤患者的临床资料,重新阅读病理组织切片,总结其临床、病理特点及随访情况。结果：所有患者均为乳头状瘤,可见伞细胞的一些组织学改变：空泡形成（4例）、类似于顶浆分泌的改变（1例）、细胞内粘蛋白形成（1例）和嗜酸性胞质小体形成（1例）。32例患者中随访28例,肿瘤无复发／演进的患者平均随访时间为28．9（3～61）个月。2例患者（7．1％）分别在首诊为初发乳头状瘤后5个月和18个月复发。其中1例在18个月时复发且有病灶演进为非侵袭型低级别尿路上皮癌（LGUC）。2例患者（7．1％）演进为更高级别的尿路上皮肿瘤,其中1例演进为非侵袭性LGUC（首诊后11个月）,另1例在33个月时演进为低度恶性潜能乳头状尿路上皮肿瘤,41个月时从首诊的乳头状瘤演进为了低级别泌尿上皮癌。无患者演进为黏膜下（T1）和肌层（T2）侵袭的尿路上皮癌。其中2例患者死于其他疾病。无患者死于膀胱癌。结论：膀胱尿路上皮乳头状瘤患者有较低的复发率并很少演进为膀胱尿路上皮癌,应避免给这些患者贴上癌症的“标签”。但是对于那些肿瘤没有复发和演进的患者,何时不需要再随访的问题仍需作进一步研究。     

青年人膀胱肿瘤临床病理特点及预后

目的:探讨青年人膀胱肿瘤的临床、病理特点及预后.方法:50例≤40岁青年人膀胱肿瘤患者,行经尿道膀胱肿瘤切除术39例,膀胱部分切除术治疗9例,膀胱全切+回肠代膀胱术1例,行膀胱全切术+原位新膀胱1例.结果:手术后随访半年~11年8个月,中位随访2年9个月.低度恶性倾向尿路上皮乳头状瘤复发2例;非肌层浸润性尿路上皮癌复发5例,低级别乳头状尿路上皮癌复发率为19%(3/16),进展2例;肌层浸润性尿路上皮癌复发1例.结论:青年人膀胱肿瘤良性肿瘤者比例相对较高.在青年人尿路上皮癌绝大部分为非肌层浸润性尿路上皮癌,而非肌层浸润性青年人低级别乳头状尿路复发率低于其他年龄段尿路低级别上皮癌.     

青年人膀胱肿瘤临床病理特点及预后

目的:探讨青年人膀胱肿瘤的临床、病理特点及预后.方法:50例≤40岁青年人膀胱肿瘤患者,行经尿道膀胱肿瘤切除术39例,膀胱部分切除术治疗9例,膀胱全切+回肠代膀胱术1例,行膀胱全切术+原位新膀胱1例.结果:手术后随访半年~11年8个月,中位随访2年9个月.低度恶性倾向尿路上皮乳头状瘤复发2例;非肌层浸润性尿路上皮癌复发5例,低级别乳头状尿路上皮癌复发率为19%(3/16),进展2例;肌层浸润性尿路上皮癌复发1例.结论:青年人膀胱肿瘤良性肿瘤者比例相对较高.在青年人尿路上皮癌绝大部分为非肌层浸润性尿路上皮癌,而非肌层浸润性青年人低级别乳头状尿路复发率低于其他年龄段尿路低级别上皮癌.     

超声造影检查在肾脏非典型占位性病变诊断中的价值

目的:探讨超声造影检查对肾脏非典型占位性病变的诊断价值。方法:回顾性分析2015年5月至2019年6月北京大学第一医院收治的44例肾脏非典型占位性病变患者的常规超声和超声造影检查资料。男26例,女18例。年龄(55.9±13.7)岁。44例共47个占位,均行常规超声检查观察肿物的位置、大小、回声、边界、彩色血流情况,做出常规超声诊断。行超声造影检查观察肿物增强时相、增强水平、增强模式、是否有环状增强,做出超声造影诊断。将超声检查诊断与最终病理或临床诊断进行比较。绘制受试者工作特征(ROC)曲线,比较常规超声和超声造影检查对肾脏非典型占位性病变的诊断效能。结果:本研究47个病灶中,诊断为恶性15个,良性32个。19个病灶经手术病理诊断,分别为肾细胞癌13个、肾淋巴瘤2个、肾囊肿3个、炎性肉芽肿1个;28个经增强CT或MRI检查诊断为良性肿瘤或假性肿瘤,且定期随访≥1年无变化,分别为血管平滑肌脂肪瘤5个、囊肿15个、肾连接部皮质缺损3个、肾柱肥大2个、未萎缩肾实质1个、驼峰肾1个、瘢痕1个。常规超声检查病灶最大径(2.5±1.3)cm。肾细胞癌常规超声检查以低回声多见(8/13);超声造影检查以快进快出为主(9/13),多为不均匀低增强(6/13),9个发现假包膜,6个发现坏死。2个肾淋巴瘤常规超声检查均为低回声;超声造影检查均为快进快出,等增强1个,低增强1个。5个肾血管平滑肌脂肪瘤常规超声检查为高回声;超声造影检查以慢进慢出为主(4/5),低增强2个,高增强2个,等增强1个。肾囊肿常规超声检查以无回声多见(16/18);超声造影检查,单纯性肾囊肿无增强,复杂性肾囊肿囊壁或分隔薄且均匀强化,呈慢进慢出、等增强或低增强。炎性肉芽肿常规超声检查呈囊实性;超声造影检查实性部分与肾实质同步强化,呈低增强。肾柱肥大、驼峰肾和局限性未萎缩肾实质常规超声检查为低回声;超声造影检查为与肾实质同进同出的均匀等增强,无明显包块轮廓出现。肾连接部皮质缺损和瘢痕常规超声检查为高回声,超声造影检查自始至终无增强。常规超声检查将1个炎性肉芽肿、1个未萎缩肾实质、2个复杂肾囊肿误诊为恶性,2个高回声肾细胞癌误诊为良性;超声造影检查仅将1个炎性肉芽肿误诊为恶性。常规超声检查对良恶性病变诊断的敏感性为86.7%,特异性为87.5%,准确性为87.2%,ROC曲线下面积0.871。超声造影检查对良恶性病变诊断的敏感性为100.0%,特异性为96.9%,准确性97.9%,ROC曲线下面积为0.984。常规超声与超声造影检查的ROC曲线下面积比较差异有统计学意义(P=0.03)。结论:超声造影检查对肾脏非典型占位性病变的诊断效能优于常规超声检查,对于常规超声检查诊断困难的肾肿瘤,以及酷似肾占位病变的良性病变和解剖异常的诊断和鉴别诊断具有优势。     

尿纤维连接蛋白试纸诊断膀胱尿路上皮癌的价值

目的 研究尿纤维连接蛋白试纸（FN试纸）诊断膀胱尿路上皮癌的灵敏度和特异度,探讨其与膀胱尿路上皮癌各项临床指标之间的关系,为进一步无创性地诊断、随访膀胱尿路上皮癌提供依据.方法 运用自主研制的FN试纸测定膀胱尿路上皮癌患者、良性泌尿系疾病患者、正常体检人群尿液纤维连接蛋白.结果 FN试纸诊断膀胱尿路上皮癌的敏感度和特异度分别为72.94%和79.03%,其阳性预测值和阴性预测值分别为85.67%和68.06%;尿液细胞学诊断膀胱尿路上皮癌的特异度较高（100%）,但其敏感度仅为47.06%.结论 FN试纸检测对不同分化及浸润深度的膀胱尿路上皮癌有着较高的灵敏度与特异度,诊断价值高于尿液液基细胞学检查,但不能对膀胱肿瘤的分级以及病灶数量进行检测.     

超声造影对肝脏占位性病变的诊断价值

目的探讨超声造影对肝脏占位性病变良、恶性鉴别诊断的价值。方法 2018年5月至2019年10月对30例肝脏占位性病变病人经外周肘静脉注射造影剂Sono Vue行超声造影检查,依据病变的造影开始增强时间、达峰时间及开始消退时间对其进行良恶性鉴别诊断,并分析不同类型肝脏占位性病变的增强模式。结果以手术或穿刺病理确诊病变类型:恶性病变21个(肝细胞性肝癌14个,胆管细胞性肝癌1个,转移性肝癌6个),以穿刺病理或随访MR/CT临床诊断良性病变11个(肝血管瘤9个,肝脏局灶性结节增生1个,肝硬化结节1个)。超声造影正确诊断恶性病变21个,正确诊断良性病变10个。恶性病变开始增强时间(12.76±2.68 s vs. 16.12±3.82s)、达峰时间(23.18±3.57 s vs. 42.78±10.46 s)、开始消退时间(40.69±8.42 s vs. 78.35±14.63 s),大部分恶性病变明显早于良性病变,但有小部分不同类型病变间有交叉。结论超声造影对肝脏占位性病变良、恶性的鉴别诊断准确率较高,具有较高的应用价值。     

经直肠多普勒超声及超声造影在鉴别前列腺良恶性结节中的应用价值

目的 探讨经直肠多普勒超声及超声造影检查鉴别前列腺良恶性结节的临床价值.方法 应用彩色和能量多普勒超声(PDUS)及血流分析软件,记录52例患者共67个前列腺结节的峰值血流指数(PVI),比较不同超声条件下前列腺良恶性结节组问PVI的差异.经直肠超声造影检查观察结节及其周围腺体组织造影增强模式,并对外腺低回声病灶行穿刺病理检查. 结果52例患者超声检出前列腺恶性结节32个,良性结节35个,恶性结节PVI为0.38±0.16、良性结节0.24±0.10(P=0.0023);PDUS检测PVI分别为0.55±0.18、0.32±0.21(P<0.01),ROC曲线下面积0.817,95%,可信区间0.704～0.901.超声造影检查30个良性结节表现为与周围实质同步灌注,增强强度低于或接近周围实质;32个恶性结节表现为灌注早于周围实质,增强强度高于周围内外腺实质.结论 PDUS检测定量参数PVI是鉴别前列腺良恶性结节的有效指标,经直肠超声造影检查有助于前列腺外腺良恶性结节的鉴别诊断.     

肾嫌色细胞癌的超声造影表现

目的 分析肾嫌色细胞癌的超声造影特征,提高对该肿瘤的识别.方法 分析经手术病理证实的28例嫌色细胞癌超声造影资料,分析血供情况及造影特征,并进行时间-强度曲线参数分析.结果 28例嫌色细胞癌与肾皮质作参照均呈乏血供造影表现,且肿块呈不均匀增强,肿块局部呈"快进快出"造影表现,强化程度低于周围肾皮质,其中15例(54%)病灶内可出现辐射样分布的强回声带.时间-强度曲线显示嫌色细胞癌组曲线达峰绝对值、曲线下面积低于肾皮质(P＜0.05),造影剂到达时间、达峰时间、曲线上升支斜率高于肾髓质组(P＜0.05).结论 超声造影检查中,肾嫌色细胞癌瘤体内辐射状增强和瘤体呈乏血供型增强为诊断提供了依据.

Abstract：

Objective To discuss the imaging characteristics of chromophobic cell renal carcinoma (CCRC) and study the features on the contrast-enhanced ultrasound (CEUS). Methods The CEUS features of CCRC in 28 cases identified by pathology were reviewed. The blood supply and enhancement characteristic were observed and analyzed on time intensity curve parameters. Results The 28 cases of CCRC showed poor blood supply in contrast with the renal cortex. The CCRC presented with heterogeneity enhancement, part of the tumor took on a high wash-in and wash-out, and enhanced less intense than the surrounding renal cortex. The actinomorphous strong echo of the tumors might be revealed with CEUS in 15 cases (54%). The time intensity curve analysis demonstrated that the CCRCs' difference of peak intensity and area under the curve were lower than the renal cortex (P＜0.05), but arrival time, time-to-peak and slope of ascending curve were higher than the renal medulla (P＜0.05). Conclusion The actinomorphous enhancement and poor blood supply in the tumor of CEUS could provide diagnostic evidence for CRCC.     

WHO2004膀胱非浸润乳头状泌尿上皮肿瘤病理分级和预后的关系

目的：研究WHO2004膀胱非浸润乳头状泌尿上皮肿瘤病理分级和预后的关系。方法：回顾性分析了2003-2007年收治的229例病理检查证实为膀胱非浸润乳头状泌尿上皮肿瘤的病例资料,其中乳头状瘤39例,低恶潜能乳头状泌尿七皮肿瘤（PUNLMP）62例,乳头状泌尿上皮低级别癌（LGPUC）72例,乳头状泌尿上皮高级别癌（HGPUC）56例。结果：乳头状瘤、PUNLMP、LGPUC和HGPUC的复发率及进展率分别为5％（2／39）、18％（11／62）、33％（24／72）、50％（28／56）和0（0／39）、0（0／62）、10％（7／72）和20％（11／56）,肿瘤的复发率和进展率在各病理分缄之间差辑有统计学意义（P〈0.01）。结论：WHO2004的病理分级能较好反映膀胱非浸润乳头状泌尿上皮肿瘤的侦后情况。     

Prognostic significance in substaging ofT1 urinary bladder urothelial carcinoma on transurethral resection

T1 papillary urothelial carcinomas of the urinary bladder run a variable clinical course, and an effective substaging system has not been defined yet. This study was conducted to devise an easy-to-use substaging method and to validate its prognostic value in T1 cancer on transurethral resection specimens. A total of 103 cases of T1 low-grade papillary urothelial carcinoma and 406 cases of T1 high-grade papillary urothelial carcinoma from a series of 1515 non-muscle-invasive bladder tumors treated by transurethral resection were studied. Substaging was performed using 0.5, 1.0, and 1.5 mm as thresholds to distinguish extensive from focal invasion. Correlations to recurrence, progression, cancer-specific mortality, and all-cause mortality were explored and compared with Ta tumors. All lamina propria invasions in low-grade papillary urothelial carcinomas were confined to 1.0 mm. The proportions of T1 high-grade papillary urothelial carcinoma invading beyond 0.5, 1.0 (T1>1 mm), and 1.5 mm were 53%, 32%, and 27%, respectively. No prognostic differences were found between Ta and T1 low-grade papillary urothelial carcinomas. T1>1 mm high-grade papillary urothelial carcinomas were associated with significantly greater risks for recurrence, progression, cancer-specific mortality, and all-cause mortality compared with T1≤1 mm and Ta tumors. Comparable statistical results could be obtained using 0.5 and 1.5 mm as cutoff points, but we recommend using 1.0 mm for practical consideration. Taking all non-muscle-invasive urothelial neoplasms of the bladder into consideration, 5 prognostically distinct categories can be established: (1) papillary urothelial neoplasms of low malignant potential; (2) low-grade papillary urothelial carcinoma Ta/1; (3) high-grade papillary urothelial carcinoma Ta; (4) high-grade papillary urothelial carcinoma T1≤1 mm; and (5) high-grade papillary urothelial carcinoma T1>1 mm. Our study demonstrates that the substaging of T1 bladder cancer is feasible, based on the evaluation of transurethral resection specimens, and can provide more precise prognostic information to identify a subset of patients with a more unfavorable prognosis.     

Rhabdomyosarcoma of the urinary bladder in adults: predilection for alveolar morphology with anaplasia and significant morphologic overlap with small cell carcinoma

Rhabdomyosarcoma (RMS) represents the most common malignant soft tissue tumor in children and adolescents with the urinary bladder representing a frequent site. Most of these urinary bladder tumors are embryonal RMS, predominantly the botryoid subtype. RMSs of the urinary bladder in adults are distinctively rare and the subject of only case reports. We report the clinicopathologic features of 5 bladder neoplasms with rhabdomyosarcomatous differentiation in adults and emphasize the differential diagnosis in the adult setting. The patients, 4 men and 1 woman, ranged in age from 23 to 85 years (mean 65.4 y). Gross hematuria was the most common initial symptom, although 2 patients had metastatic disease at presentation. Four cases were pure primary RMSs of the bladder and 1 case was a sarcomatoid urothelial carcinoma with RMS representing the extensive heterologous component. All 5 cases demonstrated a diffuse growth pattern (ie, non-nested), of which 4 cases had nuclear anaplasia (Wilms criteria without the atypical mitotic figure requirement); only 1 case (the sarcomatoid carcinoma) showed obvious rhabdomyoblastic differentiation (ie, strap cells). Three cases were of the alveolar subtype (1 admixed with embryonal histology) and 2 were RMS, not further classified. Microscopically, all tumors had a primitive undifferentiated morphology with cells containing scant cytoplasm, varying round to fusiform nuclei with even chromatin distribution, and frequent mitoses. The degree of morphologic overlap with small cell carcinoma of the bladder, a relatively more common round cell tumor in adults, was striking. The epithelial component of the sarcomatoid carcinoma was high-grade invasive urothelial carcinoma with glandular differentiation. No other case had previous history of bladder cancer or concurrent carcinoma in situ or invasive urothelial carcinoma. All tumors showed immunohistochemical expression for desmin, myogenin, and/or MyoD1. Synaptophysin was performed in 4 cases, and 3 showed weak cytoplasmic immunoreactivity. Two patients received chemotherapy, 2 underwent cystectomy, and 1 had transurethral resection alone. Outcome data were available in 4 cases, and all 4 died of disease (1, 4, 8, and 8 mo). In conclusion, (1) RMS of the urinary bladder in adults more commonly presents as a primitive round blue cell neoplasm that has significant morphologic and immunohistochemical overlap with small cell carcinoma of the bladder. (2) Although RMS in children generally have a botryoid embryonal histology with favorable outcome, bladder RMS in adults frequently demonstrates alveolar or unclassified histology, commonly with anaplasia, and have a uniformly aggressive clinical course.     

Neuerungen in der histologischen WHO-Klassifikation urothelial Harnblasentumoren und abnormer flacher Urothelläsionen

Recently the World Health Organization published a new classification of urinary bladder tumors which is intended to take into account better the biology of the various lesions and to better distinguish between clearly benign and malignant lesions.We examine the possible diagnostic and clinical impact of the new classification, including recent immunohistochemical findings.Papillary urothelial lesions include papillomas, papillary neoplasms of low malignant potential, and papillary carcinomas. Flat urothelial lesions include hyperplasia, reactive atypia/atypia of unknown significance, dysplasia, and carcinoma in situ. Invasive patterns of papillary carcinomas are discussed, with special emphasis on lamina muscularis mucosae substaging.The most important feature of the new classification is its differentiation of two types of low-grade, noninvasive papillary urothelial lesions: papillary neoplasm of low malignant potential vs. papillary carcinoma. Long-term follow-up studies are needed to determine the clinical significance of this differentiation.     

Significance of denuded urothelium in papillary urothelial lesions

Flat urothelial carcinoma in situ (CIS) is often characterized by prominent dyscohesion with some cases having only a few clinging CIS cells remaining on biopsy. The finding of extensive denudation on urothelial biopsies is associated with a risk of CIS on either prior or subsequent biopsies. The significance of denudation in papillary urothelial lesions has not been formally studied. We identified from our surgical pathology files 31 specimens (from 28 patients) of papillary urothelial lesions with extensive denudation. In cases in which denudation was associated with low-grade urothelial neoplasms, follow-up of subsequent cytologic and histologic specimens was obtained. Of the 28 patients, 25 (89%) were men and 3 (11%) were women with an age range of 40 to 88 years old (mean age 62). Of 31 biopsies, 15 were from anatomically confined areas (ie, renal pelvis, ureter, and urethra). In 22/28 (79%) patients, prominent denudation was associated with high-grade papillary carcinomas, 4/28 (14%) low-grade papillary carcinomas, and 2/28 (7%) papillary urothelial neoplasms of low-grade malignant potential. The average extent of urothelial denudation was 82% with 61% of cases having > or =90% denudation. Prominent cautery artifact was present in 17/31 (55%) cases. In 13/28 patients with high-grade lesions, there was a concurrent biopsy of a second urothelial lesion that was either high-grade papillary urothelial carcinoma or invasive urothelial carcinoma. Five of the 6 patients in which the prominent denudation was associated with a low-grade papillary urothelial lesion have not progressed to a high-grade lesion. One patient with a denuded papillary urothelial neoplasm of low malignant neoplasm was subsequently diagnosed with a noninvasive low-grade papillary urothelial carcinoma in the bladder and a high-grade infiltrating urothelial carcinoma of the ureter. We conclude that (1) the majority of papillary urothelial lesions associated with prominent urothelial denudation are high grade; (2) a significant percentage of papillary urothelial lesions with denudation occur with either prominent cautery artifact or in anatomically confined areas, suggesting both iatrogenic and mechanical contributing factors, respectively; (3) a minority of cases with prominent urothelial denudation occur in association with low-grade papillary urothelial lesions and are not associated with progression to higher grade lesions on follow-up studies; and (4) prominent urothelial denudation in papillary lesions should prompt careful examination of these specimens for rare clinging high-grade carcinoma cells, although in a minority of cases the underlying lesion will be low grade.