肝内胆管癌的腹腔淋巴结清扫

正肝内胆管癌(intrahepatic cholangiocarcinoma,ICC)是胆管上皮细胞起源的恶性肿瘤,是仅次于肝细胞癌的第2常见的肝脏原发恶性肿瘤。ICC在临床上较少见,但发病率和死亡率呈上升趋势~([1])。ICC具有较高侵袭转移能力,预后较差,是临床较为棘手的肝脏恶性肿瘤。许多患者在发现ICC时常合并血管侵犯、周围神经侵犯、多发肝内转移或者肝外转移~([2])。不能手术     

肾上腺转移癌(附11例报告)

目的　探讨肾上腺转移癌的临床特点与诊治方法。　方法　回顾分析 1993年 12月至2 0 0 3年 3月肾上腺转移癌患者 11例的诊治结果。原发灶为肺癌 4例 ,肝癌 5例 ,胆管癌 1例 ,肾癌 1例。临床表现腰背部胀痛 3例 ,乏力、消瘦 3例 ,血尿 1例 ,无症状者 4例。 11例行B超及CT检查 ,2例行正电子发射断层扫描 (PET)检查。 11例均行手术治疗 ,肿瘤完整切除 9例 ,姑息性切除 1例 ,双侧转移者仅行左侧切除 1例。　结果　完整切除转移癌 9例中 5例生存 6～ 6 3个月 ,平均 34个月 ;2例已分别存活 2及 16个月 ,仍在随访中 ;2例失访。 1例行姑息性切除者生存 3个月 ,1例双侧肾上腺转移癌仅行左侧切除者生存 4个月。　结论　B超及CT是诊断肾上腺转移癌的重要检查方法 ,PET对诊断肾上腺转移癌有较高的临床价值。手术切除转移灶是延长患者生存期的最有效方法。     

肝移植治疗胆管细胞癌的疗效评价

目的 评价原位肝移植治疗胆管细胞癌的疗效,并分析影响预后的因素.方法 回顾性分析上海长征医院2001年12月至2006年12月问接受OLT的234例肝癌患者的临床资料,其中胆管细胞癌(cholangiocarcinoma,CC)患者6例,包括肝内胆管癌4例,肝门部胆管癌2例.结果 6例患者随访1～56个月,死亡5例(肿瘤复发2例,严重并发症3例).患者的0.5、1和2年累积存活率分别为4/6,3/6和1/6,无瘤存活率分别为3/6,2/6和1/6,患者的平均及无瘤生存时间均为(14±4)个月.结论 胆管细胞癌肝移植患者预后较差,须谨慎对待.     

MTSS1在胆管癌组织中的表达及其与预后关系

目的 探讨MTSS1在胆管癌组织中的表达及其与预后关系.方法 收集2003年1月至2005年12月第二军医大学东方肝胆外科医院手术切除的49例肝门部胆管癌患者的胆管标本,构建肝门部胆管癌组织芯片和10例对应癌旁正常胆管上皮的组织芯片,免疫组织化学染色方法检测MTSS1的表达情况;并以脂质体法转染胆管癌细胞株RBE,Western blot法检查MTSS1蛋白表达情况,MTT法检查RBE细胞增殖能力.患者采用门诊和电话随访,随访时间截至2012年5月.计量资料采用t检验,计数资料采用x2检验,Kaplan-Meier法绘制生存曲线,单因素生存分析采用Log-rank检验,多因素生存分析采用COX回归模型.结果 免疫组织化学染色结果显示:MTSS1在癌旁正常胆管上皮组织中的表达率为10/10,而在胆管癌组织中的表达率仅为59.2％(29/49).转染MTSS1的胆管癌细胞增殖比率为1.55 ±0.05,低于没有转染MTSS1的胆管癌细胞的2.32 ±0.08(=4.454,P＜0.05).性别、年龄、TNM分期、T分期、组织分化、神经侵犯、肿瘤直径等不影响MTSS1的阳性表达(r=0.211,3.471,0.507,0.507,0.368,0.882,0.660,P ＜0.05),而淋巴结转移则影响MTSS1的阳性表达(x2=10.436,P＜0.05).所有患者随访1～59个月,中位随访时间16个月.MTSS1阳性表达患者中位无瘤生存时间为17.9个月,MTSS1阴性表达患者为11.3个月,两者比较,差异无统计学意义(Log-rank值=3.707,P＞0.05).MTSS1阳性表达患者中位生存时间为34.9个月,而MTSS1阴性表达患者仅有18.7个月,两者比较,差异有统计学意义(Log-rank值=5.671,P＜0.05).多因素生存分析结果显示:MTSS1表达不是影响患者预后的独立危险因素(x2=0.406,P＞0.05).结论 MTSS1在胆管癌原发灶中表达下降,与淋巴结转移呈负相关,是判断胆管癌患者预后的重要指标.     

中下段胆管癌切除后切缘阳性的意义及预后因素分析

目的 分析中下段胆管癌切除术后切缘阳性的意义,研究影响中下段胆管癌切除术后的预后因素.方法 回顾性分析1990年1月至2006年12月收治的79例中下段且日管癌切除患者的临床病理资料.其中男性53例、女性26例,年龄30～79岁,平均61岁.中段胆管癌34例,下段胆管癌45例.行胰十二指肠切除术46例,行根治性胆总管癌切除术25例,行根治性胆总管癌切除联合肝部分切除术6例,行根治性胆总管癌切除联合门静脉部分切除术2例.5例于术后1个月内死亡,对其余74例患者的15项临床病理特征进行单因素及多因素分析.结果 74例患者总的5年生存率为30.7%,中位生存期为36个月.术后病理榆查为镜下切缘阳性(R1切除)16例(20.3%),其中肝脏端胍管切缘阳性6例,远端胆管切缘阳性3例,双侧胆管切缘阳性2例,环周切缘阳性5例.接受R0和Rl切除的患者的5年生存率分别为34.4%和15.5%.10例(17.2%)R0切除的胆管癌出现局部复发,10例(62.5%)R1切除出现复发,差异有统计学意义(X2=13.024,P<0.01).单因素分析显示术前血红蛋白水平、分化程度、肿瘤浸润深度、淋巴结转移、TNM分期及手术切缘为影响预后的因素.多因素分析显示淋巴结转移状况和切缘癌残留是影响预后的独立因素.结论 中下段胆管癌根治术中冰冻病理检查切缘达R0切除是提高长期生存的重要策略,辅助治疗的效果尚待进一步研究.     

Survivin在胆管癌中的表达

目的　探讨Survivin基因表达与胆管癌发生发展的关系。方法　应用免疫组织化学技术 (SP法 )检测Survivin基因在 3 3例胆管癌标本、2 8例癌旁胆管组织和 5例胆管良性病变标本中的表达。结果　 3 3例胆管癌组织中Survivin阳性表达率为 72 .7% ( 2 4/3 3 ) ;在癌旁胆管组织和胆管良性病变组织中未检测到Survivin的表达 ,胆管癌组织、癌旁胆管组织、胆管良性病变组织之间的Survivin基因的表达差异有非常显著性 (P <0 .0 1)。Survivin基因的表达与患者的性别、年龄、肿瘤的大小、分化及是否转移无关。结论　Survivin在胆管癌中高度表达可能与胆管癌的发生发展有关 ,与预后的关系有待进一步的探讨。     

肿瘤侵犯大血管的外科治疗

目的　探讨累及大血管的肿瘤切除及受侵犯血管的处理方法 ,以提高肿瘤的切除率及术后生存率。方法　总结 1998年 10月～ 2 0 0 4年 2月的 2 6例累及重要血管的肿瘤切除及血管重建的经验。结果　 2 6例患者均无术后人工血管感染 ,血肿形成等。获随访 2 3例 ,随访时间 2～ 65个月 ,平均 42 .8个月。术后随访分别行彩色超声或CT血管显影 (CTA )检查 ,5例胰头癌和 1例胆管癌患者下腔静脉、门静脉置换后 ,3例分别于术后 3～ 15个月并发癌栓形成 ,术后远期通畅率为 5 0 % ,肿瘤分别于术后 3～ 3 1个月复发。 7例盆腔和腹膜后肿瘤切除血管置换患者术后获随访 2年 ,1例复发 ,但血管通畅。 2例四肢肉瘤患者随访 1年未见复发 ,血管通畅。 11例颈部肿瘤切除、血管置换患者术后随访 3个月至 5年 ,目前血管通畅 ,肿瘤未见复发。结论　对累及重要血管的肿瘤患者行肿瘤切除并大血管切除重建手术是安全的 ,可明显提高切除率、降低复发率 ,延长存活时间。     

远端胆管癌根治术中行扩大淋巴结清扫的预后评价

作者回顾性研究了 2 6例行胰十二指肠切除远端胆管癌患者 ,术中进行了区域性和主动脉旁淋巴结清扫 ,其中主动脉旁清扫范围从腹腔干至肠系膜下动脉 ,从下腔静脉右侧缘至腹主动脉左侧缘。对所切除的标本进行病检 ,观察并记录受到癌侵犯淋巴结的数目及位置 ,同时观察胰腺颈部、胆管近端和导管周围软组织的切缘有无癌侵犯。结果显示有 6例患者 (2 2 % )出现了手术并发症 ,5例为胰管空肠瘘 ,2例腹腔内出血 ,1例心肌梗塞 ,1例胃空肠输出袢梗阻。有 15例患者的淋巴结有癌转移 ,其中 6例有 1- 2个淋巴结癌转移 ,9例有 3个以上淋巴结癌转移 ,转移范围…     

联合肝叶和肝门血管切除治疗肝门胆管癌

目的　探讨治疗肝门胆管癌理想的肝叶切除术式 ,以期提高其疗效、降低并发症和病死率。方法　对 16例侵犯肝门血管的肝门胆管癌 ,采用肝I ,IV段连同肝门胆管肿瘤与受侵血管整块切除及肝十二指肠韧带骨骼化淋巴清扫。结果　 15例获手术切除 ,切除率为 93 .8% ,12例获R0 切除。无手术死亡和住院死亡。发生暂时性胆漏 1例 ,腹腔感染 1例 ,并发症发生率为 13 .3 % ,均行非手术治愈。随访病例中位生存期为 2 2个月 ,7例尚存活。结论　合并肝叶、肝门血管切除可提高肝门胆管癌的切除率和生存率 ;肝中叶和肝尾叶是肝门胆管癌手术联合切除的主要部位。肝门受侵血管的切除对提高该病切除率和根治率是有意义的 ,应酌情重建或不重建肝门血管。     

单中心11例肝内胆管细胞癌肝移植疗效分析

目的 评价肝内胆管细胞癌患者肝移植的疗效,并分析其预后因素.方法 回顾性分析中山大学附属第三医院2003年10月至2008年12月间11例肝内胆管细胞癌肝移植患者的临床资料,采用Kaplan-Meier生存率分析肝移植术后患者存活率及无瘤存活率. 结果 11例术后均得到随访,肝移植术后生存时间2.5～53个月,中位生存时间为9.0个月,其受者1、2、3、4年无瘤存活率分别为51.9%、51.9%、51.9%、51.9%,1、2、3、4年累积存活率分别为50.5%、50.5%、50.5%、50.5%.围手术期死亡率为0,肿瘤复发率45.5%,肿瘤复发患者存活2.5～lO个月(平均7.5个月),无瘤生存1～8个月(平均3.8个月).结论 肝内胆管细胞癌患者施行肝移植的预后不良,有淋巴结转移或门静脉侵犯或胆管侵犯者,应列为肝移植禁忌证.     

Perineural Invasion Is a Prognostic Factor in Intrahepatic Cholangiocarcinoma

Background  Perineural invasion is commonly observed in biliary tract cancer and is an independent prognostic factor. Since intrahepatic cholangiocarcinoma (ICC) develops from biliary epithelia in the liver, ICC may share the same characteristics in terms of the prognostic implications of perineural invasion. The aim of this study was to evaluate the clinical significance of perineural invasion in ICC. Methods  A total of 59 patients with ICC who underwent hepatectomy were retrospectively reviewed. The numbers of nerves with and without tumor involvement were counted. The perineural invasion index (PNI) was calculated as the number of involved nerves divided by the total number of nerves examined. Predictors for perineural invasion and prognostic factors were analyzed. Results  Perineural invasion was observed in 47 of 59 (80%) patients, and the median PNI was 0.082. The macroscopic tumor appearance and tumor location were significantly associated with perineural invasion (p = 0.013 and 0.032, respectively). Univariate and multivariate analyses (excluding seven in-hospital deaths) revealed that histologic grade, the presence of perineural invasion, nodal metastasis, and intrahepatic metastasis were independent prognostic factors. The survival rate of the patients with (n = 42) or without (n = 10) perineural invasion was 17 and 80% at 3 years; and 17 and 70% at 5 years, respectively (p = 0.001). Conclusion  Perineural invasion is frequently found in patients with ICC and is an independent prognostic factor. ICC is an aggressive tumor similar to other biliary tract cancers. Because perineural invasion is a histologic marker of aggressiveness, it potentially has a role as a determinant of patient selection for adjuvant therapy.     

Surgical Outcome and Prognostic Factors in Intrahepatic Cholangiocarcinoma

BACKGROUND: The clinicopathologic features and surgical outcome of intrahepatic cholangiocarcinoma are not fully understood. METHODS: Fifty-six consecutive patients with intrahepatic cholangiocarcinoma who underwent surgical resection at the National Cancer Center Hospital East between October 1992 and July 2007 were retrospectively analyzed. Intrahepatic cholangiocarcinomas were subdivided into solitary tumors and tumors with intrahepatic metastasis. RESULTS: Complete tumor removal (R0 resection) was performed in 42 patients (75%). The 5-year survival rate for patients with intrahepatic cholangiocarcinoma (n = 56), patients with a solitary tumor (n = 46), and patients with intrahepatic metastasis (n = 10) were 32, 38, and 0%, respectively. There was a significant difference in survival between patients with a solitary tumor and those with intrahepatic metastasis (p < 0.0001). The 5-year survival rate for patients with stage I (n = 3), II (n = 9), III (n = 15), and IV disease (n = 26) was 100, 67, 37, and 0%, respectively. There was a significant difference in survival between stage I and stage IV (p = 0.011), between stage II and stage IV (p = 0.0002), and between stage III and stage IV (p = 0.0015). The most frequent site of recurrence was the liver. Univariate analysis showed that intrahepatic metastasis, portal vein invasion, hepatic duct invasion, lymph node metastasis, perineural invasion, and positive surgical margin (R1) were significantly associated with poor survival. Multivariate analysis confirmed that intrahepatic metastasis was a significant and independent prognostic indicator after surgical resection for intrahepatic cholangiocarcinoma (p = 0.001). No patient with intrahepatic metastasis survived more than 10 months in this study. CONCLUSIONS: Intrahepatic metastasis was the strongest predictor of poor survival in intrahepatic cholangiocarcinoma.     

Perineural Invasion of Cutaneous Malignancies

BACKGROUND: Perineural invasion is an important mode of tumor spread and is associated with increased aggressiveness and a propensity for recurrence among cutaneous malignancies. OBJECTIVE: To review the pathogenesis, diagnosis, and treatment of cutaneous tumors exhibiting perineural invasion. METHODS: This article is based on a review of the medical literature concerning tumors with perineural involvement. RESULTS: This article describes the clinical signs and histologic features of cutaneous malignancies exhibiting perineural involvement. CONCLUSION: Appropriate patient care mandates consideration of perineural invasion in the evaluation of cutaneous tumors. As the majority of patients present without symptoms of neural involvement, physicians must be vigilant in the search for this type of tumor spread.     

Long-term survival and prognostic factors in the surgical treatment of mass-forming type cholangiocarcinoma

BACKGROUND: Mass-forming type cholangiocarcinoma is a distinct from of cholangiocellular carcinoma, with pathologic and biologic behavior different from those of other types. The clinical consequences of these differences have never been clarified. METHODS: Fifty-two consecutive patients (32 men and 20 women, mean age 62 years) with mass-forming type cholangiocarcinoma that had been treated with curative surgical resection between 1980 and 1998 were retrospectively evaluated. Long-term survival and disease-free survival were calculated, and univariate and multivariate analysis of various prognostic factors was conducted. RESULTS: The 30-day postoperative mortality rate was 2%, and the overall and disease-free 5-year survival rates were 36% and 34%, respectively. Univariate analysis identified 5 significant risk factors for overall survival: surgical margin, lymph node metastasis, lymph node dissection, vascular invasion, and left-side location of the main tumor. Two risk factors were identified for disease-free survival: surgical margin and lymph node metastasis. Multivariate analysis confirmed that surgical margin, lymph node metastasis, and vascular invasion were independently significant variables for overall survival. CONCLUSIONS: This is the first reported study on the effectiveness of liver resection for the treatment of mass-forming type cholangiocarcinoma, showing that surgical therapy can prolong survival if local radicality can be achieved and lymph-node metastases are absent.     

Perineural Invasion in Extrahepatic Cholangiocarcinoma: Prognostic Impact and Treatment Strategies

Background

The significance of perineural invasion in extrahepatic cholangiocarcinoma has not been fully elucidated. This study aims to determine the prognostic impact of and optimal treatment strategy for perineural invasion in patients with extrahepatic cholangiocarcinoma.

Methods

Medical records of 133 patients with extrahepatic cholangiocarcinoma who underwent curative resection were reviewed retrospectively. Ninety-eight patients had perineural invasion and 35 patients did not. Univariate and multivariate survival analyses were performed to clarify the prognostic impact of and optimal treatment strategy for perineural invasion.

Results

Only tumor differentiation (P?=?0.024) was independently associated with perineural invasion in the multivariate logistic regression model. Multivariate survival analysis revealed that perineural invasion (P?=?0.002), resection margin status (P?=?0.016), and International Union Against Cancer (UICC) pT factor (P?=?0.015) were independent prognostic factors of overall survival. Overall 5-year survival rates for patients with and without perineural invasion were 28 and 74 %, respectively. Among 98 patients with perineural invasion, the use of adjuvant chemotherapy (P?=?0.003), lymph node status (P?=?0.015), resection margin status (P?=?0.008), and UICC pT factor (P?=?0.016) were independently associated with overall survival by multivariate analysis. Overall 5-year survival rates for patients with perineural invasion who did and did not receive adjuvant chemotherapy were 33 and 21 %, respectively (P?=?0.023).

Conclusions

Perineural invasion is a potent prognostic factor in extrahepatic cholangiocarcinoma. Adjuvant chemotherapy may improve the overall survival of patients with perineural invasion.     

Reexcision perineural invasion. Not a sign of malignancy

Perineural invasion has been reported to occur in both benign and malignant neoplasms. We describe two cases in which perineural invasion by epithelial cells was present in reexcision skin specimens removed because of melanocytic lesions in the original biopsy material. Because of the absence of a primary epithelial neoplasm, this phenomenon was interpreted as a reactive or reparative process, most probably resulting from regenerating traumatized sweat gland ducts. On the basis of this study alone, it may not be possible to distinguish between reexcision perineural invasion and perineural invasion from a primary epithelial neoplasm. For such cases, the following histologic features serve as provisional guidelines favoring an interpretation of reexcision perineural invasion: absence of perineural spread beyond the immediate previous biopsy site, benign appearance of the perineural epithelial cells different from the appearance of the original tumor, and absence of residual epithelial tumor in the vicinity of the involved perineurium.     

Intraductal papillary growth of liver metastasis originating from colon carcinoma in the bile duct: report of a case

Morphologically, liver metastases from colorectal carcinoma usually form as nodular tumor masses, whereas intraductal papillary growth in the bile duct is rare. A 65-year-old man underwent right hemicolectomy for advanced colon carcinoma, and histology of the primary carcinoma confirmed moderately differentiated adenocarcinoma with subserosal invasion, no vascular infiltration, and no lymph node metastasis. A liver tumor was found in the right paramedian Glisson pedicle and intraductal growth of cholangiocarcinoma was seen on imaging. We performed right hepatectomy and macroscopically, the resected specimen contained a growth in the bile duct lumen similar to cholangiocarcinoma. Histological examination revealed intraductal papillary proliferation of well-differentiated adenocarcinoma without vascular infiltration or lymph node metastasis in the hepatic hilum. Immunohistochemical staining revealed that the tumor cells were negative for cytokeratin-7 and positive for cytokeratin-20. Based on these findings, liver metastasis from colon carcinoma was diagnosed. Liver metastasis from colorectal carcinoma rarely arises as intraductal papillary growth in the bile duct, but the possibility of liver metastases with unusual morphology must be borne in mind for patients with a history of carcinoma in the digestive tract.     

Recurrence and Prognostic Factors of Ampullary Carcinoma after Radical Resection: Comparison with Distal Extrahepatic Cholangiocarcinoma

Background Ampullary carcinoma is often considered to have a better prognosis than distal extrahepatic cholangiocarcinoma. However, studies that directly compare the recurrence and histopathological features between the two groups are rare. Methods Clinicopathologic factors and the long-term outcomes of 163 patients with ampullary carcinoma after radical resection were retrospectively evaluated and compared with those of 91 patients with distal extrahepatic cholangiocarcinoma. Results Among the 163 ampullary carcinomas, T1 stage, well-differentiated tumors and perineural invasion were 45 (28%), 73 (45%), and 23 (14%), respectively, whereas, only five (6%) were T1 stage, 15 (17%) were well differentiated, and 63 (69%) showed perineural invasion (p < 0.001, for all) in distal extrahepatic cholangiocarcinomas. More patients with distal extrahepatic cholangiocarcinoma had liver metastasis than ampullary carcinoma (24% vs. 10%, p = 0.004). Multivariate analysis identified venous invasion and perineural invasion as risk factors for recurrence of ampullary carcinoma after radical resection. Only lymph node involvement was identified as a risk factor for recurrence of distal extrahepatic cholangiocarcinoma by multivariate analysis. Overall five-year survival of patients with ampullary cancer was higher than that of patients with distal extrahepatic cholangiocarcinoma (68% vs. 54%; p = 0.033). In patients without lymph node metastasis, a significant difference in survival was also observed between the two groups (p = 0.049). Conclusion Earlier diagnosis and the less frequent occurrence of pathological factors associated with tumor invasiveness in ampullary carcinoma than in distal extrahepatic cholangiocarcinoma may explain its association with a better prognosis.     

Clinicopathologic studies on perineural invasion of bile duct carcinoma.

To elucidate the clinical significance of perineural invasion on bile duct cancer, a clinicopathologic study was performed on 70 resected patients with bile duct carcinoma. The overall incidence of perineural invasion in the resected specimen was 81.4%. There seemed to be no correlation between perineural invasion and site, size of the tumor, and lymph node metastasis. A significant correlation was observed, however, between macroscopic type, microscopic type, depth of invasion, and perineural invasion. Perineural invasion index (PNI) was defined as the ratio between the number of nerve fibers invaded by cancer and the total number of nerve fibers with and without cancer invasion. Perineural invasion index was significantly higher at the center compared with the proximal and distal part of the tumor (p less than 0.001). The 5-year survival rate for patients with perineural invasion was significantly lower (p less than 0.05) than that for those without perineural invasion (67% versus 32%).     

Histologic grade and perineural invasion are more important than tumor thickness as predictor of nodal metastasis in penile squamous cell carcinoma invading 5 to 10 mm

Penile squamous cell carcinomas (SCCs) invading to a depth inferior to 5 mm usually have very low risk for regional metastasis, whereas tumors thicker than 10 mm have a high metastatic potential. A significant number of squamous cell carcinomas, however, belong to an intermediate category (5 to 10 mm in thickness) in which the incidence of regional lymph node metastasis is very difficult to predict. Consequently, a frequent clinical dilemma is whether to perform or not inguinal dissection in this group of lesions. The objective of this study was to evaluate multiple risk factors for regional metastasis in tumors 5 to 10-mm thick. One hundred thirty-four partial penectomies with invasive carcinomas 5 to 10-mm thick, all of which with corresponding inguinal lymph node dissection, were evaluated. Factors evaluated were--patient's age, anatomic site, histologic grade, tumor thickness, anatomic levels of invasion, and vascular and perineural invasion. Grades were classified as 1, well; 2, moderately; and 3, poorly differentiated. To evaluate independent significance of various prognostic factors, a logistic regression analysis was performed, and a nomogram was prepared to evaluate metastatic risk according to histologic grade and perineural invasion. Groin metastasis was found in 66 of 134 patients (49%). High histologic grade and perineural invasion were statistically significant pathologic factors associated with groin metastasis. Nodal metastases were found in 2 of 25 grade 1 (8%), 24 of 46 grade 2 (52%), and 40 of 63 grade 3 carcinomas (63%) (P value 0.0001). Of 48 patients with perineural invasion, metastasis was found in 33 cases (69%) (P value 0.001). The average tumor thickness, anatomic level of invasion, and presence of vascular invasion were not statistically significantly different in metastasizing and nonmetastasizing neoplasms. Fifty percent of tumors invading 5 to 10 mm were not associated with metastasis and may be spared a nodal dissection. In this subset of patients, high histologic grade and perineural invasion were significant and useful risk factors associated with regional metastasis. The probability of inguinal node metastasis in patients with grade 1 tumors without perineural invasion is almost nonexistent whereas for high-grade tumors associated with perineural invasion is near 80%.