Methylene blue injection into the rectal artery as a simple method to improve lymph node harvest in rectal cancer.

Adequate lymph node assessment in colorectal cancer is crucial for prognosis estimation and further therapy stratification. However, there is still an ongoing debate on required minimum lymph node numbers and the necessity of advanced techniques such as immunohistochemistry or PCR. It has been proven in several studies that lymph node harvest is often inadequate under routine analysis. Lymph nodes smaller than 5 mm are especially concerning as they can carry the majority of metastases. These small, but affected lymph nodes may escape detection in routine analysis. Therefore, fat-clearing protocols and sentinel techniques have been developed to improve accuracy of lymph node staging. We describe a novel and simple method of ex vivo methylene blue injection into the superior rectal artery of rectal cancer specimens, which highlights lymph nodes and makes them easy to detect during manual dissection. Initially, this method was developed for proving accuracy of total mesorectal excision. We performed a retrospective study comparing lymph node recovery of 12 methylene blue stained and an equal number of unstained cases. Lymph node recovery differed significantly with average lymph node numbers of 27+/-7 and 14+/-4 (P<0.001) for the methylene blue and the unstained group, respectively. The largest difference was found in size groups between 1 and 4 mm causing a shift in size distribution toward smaller nodes. Metastases were confirmed in 21 and 19 lymph nodes occurring in five and four cases, respectively. Hence, we conclude that methylene blue injection technique improves accuracy of lymph node staging by heightening the lymph node harvest in rectal resections. In our experience, it is a very simple time and cost effective method that can be easily established under routine circumstances.     

Periprostatic lymph node metastasis in prostate cancer and its clinical significance

Deng F‐M, Mendrinos S E, Das K & Melamed J
(2012) Histopathology  60, 1004–1008
Periprostatic lymph node metastasis in prostate cancer and its clinical significance Aims: To evaluate the potential of periprostatic lymph node (LN) as a staging indicator, particularly with the use of methods for enhanced detection of micrometastasis. Methods and results: We retrieved cases with periprostatic LN from radical prostatectomy specimens accrued between 1997 and 2007 at our institution. Twenty‐one (0.8%) of 2663 radical prostatectomy specimens had periprostatic LNs (total number of LNs = 22). LN size ranged from 0.8 to 4.7 mm. Most of the periprostatic LNs were located close to the posterior base. Seven (32%) of 22 LNs were involved by metastatic prostate cancer (PCa), including five detected on routine haematoxylin and ceosin slides and an additional two detected only by immunohistochemistry. Cases with periprostatic LNs had a significantly higher metastatic rate (29%; six of 21) compared to those with pelvic LNs sampled at radical prostectatomy in our institution (1.9%). When compared to cases with negative periprostatic LNs (n = 15), the tumour characteristics of cases with metastatic periprostatic LNs (n = 6) included higher tumour volume, Gleason score, stage and a greater propensity for prostate‐specific antigen (PSA) recurrence. Conclusions: Despite their infrequent identification, periprostatic LNs if detected in the radical prostatectomy specimen should be evaluated with greater scrutiny (step sections and/or immunohistochemical studies) to evaluate their prognostic potential.     

The assessment of prognosis of surgically resected oesophageal cancer is dependent on the number of lymph nodes examined pathologically

Aims:  The prognosis in surgically resected oesophageal carcinoma (OC) is dependent on the number of regional lymph nodes (LN) involved, but no guidance exists on how many LNs should be examined histopathologically to give a reliable pN status. The aim of this study was to determine whether the number of LNs examined after OC resection has a significant effect on the assessment of prognosis.
Methods and results:  Routinely generated pathology reports from 237 consecutive patients undergoing oesophagectomy for OC were examined and analysed in relation to survival. The main outcome measure was survival from date of diagnosis. Lymph node count (LNC) correlated strongly with survival; a plateau was reached after a count of 10. Median and 2-year survival was 30 months and 42%, respectively, if <10 nodes were examined ( n  = 88), compared with 51 months and 61% if >10 nodes were examined ( P  = 0.005). This effect was greatest in pN0 cases. The prognostic value of the absolute number of LN metastases (<4) and LN ratio (<0.4) was strongly dependent on a LNC of >10.
Conclusions:  These results demonstrate the importance of careful pathological examination and lymph node retrieval after OC resection. At least 10 nodes should be examined to designate an OC as pN0.     

An audit of pathology lymph node dissection techniques in pylorus preserving Kausch-Whipple pancreatoduodenectomy specimens

AIMS: To determine whether or not identifying recognised anatomical groupings of lymph nodes (LNs) improves LN yield in pancreatoduodenectomy resection specimens. METHODS: All the pathology reports from pancreatoduodenectomy resection specimens between January 1997 and September 1999, for one specialist pathologist at the Royal Liverpool University Hospital, were examined retrospectively. The total number of LNs found in each specimen was determined and the method of identifying LNs established for each case. LNs were found using either (1) the UICC TNM anatomical groupings, termed "grouped"; (2) the Japanese Pancreatic Society classification, termed "numbered"; or (3) neither the "grouped" nor "numbered" classification, termed "non-grouped". RESULTS: A total of 50 reports (45 neoplastic, five chronic pancreatitis) were studied, 11 with non-grouped LNs, 14 with grouped LNs, and 25 with numbered LNs, including the five inflammatory cases. A median of 7.0 LNs was found in non-grouped cases, a significantly lower number than in the grouped cases (median, 12.0; Mann-Whitney U, p < 0.039) and numbered cases (median, 17.0; p < 0.0001). There was no significant difference in the LN yield between grouped and numbered cases (p = 0.1066). LNs were found most frequently in the inferior, posterior pancreaticoduodenal, and infrapyloric regions. CONCLUSIONS: A detailed knowledge of the anatomical distribution of LNs in pancreatoduodenectomy resection specimens significantly improves LN yield. It is suggested that illustrations of LN sites in resection specimens should be included in pathology guidelines/proformas to improve LN detection and, therefore, pathological prognostic data.     

Resection of metachronous lymph node metastases from hepatocellular carcinoma after hepatectomy: report of four cases

We report 4 cases of surgical resection of metachronous lymph node (LN) metastases from hepatocellular carcinoma (HCC) following hepatectomy. Clinicopathological features and results of LN dissection were investigated in the 4 patients. One patient was found to have a single metastasis in the mediastinal LNs, another had multiple metastases in the mediastinal and abdominal LNs, and the other 2 had single metastases in the abdominal LN. The locations of the abdominal LN metastases were behind the pancreas head in 2 patients and around the abdominal aorta in 1 patient. They all underwent surgical resection of metastatic LNs and had no postoperative complications. The 3 patients whose LN metastases were solitary have been alive for more than 2 years after LN resection, and one of them is free from recurrence. The patient with multiple LN metastases died 13 months after LN resection due to carcinomatosis. With the expectation of long-term survival, a single metachronous LN metastasis from HCC after hepatectomy should be resected in patients without uncontrollable intrahepatic or extrahepatic tumors.     

Angiogenesis is redundant for tumour growth in lymph node metastases

AIMS: Angiogenesis is essential for the growth of solid tumours. As the role of angiogenesis is unclear in the pathogenesis of primary lymph node (LN) tumours, we wondered whether neoangiogenesis was important in supporting and promoting the growth of tumours in LNs. METHODS AND RESULTS: We investigated 16 cases of squamous carcinoma involving oral cavity (n=9) and larynx/pyriform fossa (n=7), all of whom had lymph node metastases. Sections of the primary tumour, uninvolved mucosa, metastatic LN and nonmetastatic LN were double-immunostained with factor VIII-related antigen and MIB-1. Proliferating blood vessels, i.e. neoangiogenesis, was identified by coexpression of factor VIII-related antigen-stained blood vessels and MIB-1 staining of the endothelial cell nuclei. Counts were performed in an area of 4 mm2. Primary tumours (127-188.7), uninvolved mucosa (54-84.5) and metastatic LNs (123.5-167) had significantly lower vessel counts than nonmetastatic LNs (194-253.9) (P=0.003; P < 0.001; P < 0.001, respectively). With regard to neoangiogenesis, primary tumours (1.7-5) had significantly higher counts than uninvolved mucosa (0-0.4), nonmetastatic LNs (0-0.4) and metastatic LNs (0.9-2.4) (P < 0.001; P < 0.001; P=0.047, respectively). CONCLUSIONS: Our data suggest that because of the rich native vascularity of lymph nodes, neoangiogenesis is redundant for the growth of metastatic tumour.     

Seeking a standard for adequate pathologic lymph node staging in primary bladder carcinoma

The purposes of this study are to evaluate the adequacy of pathologic lymph node (LN) staging in radical cystectomy specimens from patients with urothelial carcinoma of the bladder and to analyze the frequency of LN metastases among different anatomic regions. All radical cystectomies performed for primary urothelial bladder cancer over a 5-year period (January 2007–September 2012) at a single institution were reviewed. Particular attention was paid to the total number of LNs examined, the number and location of LNs with metastases (positive LNs), and the presence or absence of extranodal tumor extension and/or lymphovascular invasion in the cystectomy specimen. Results and data were analyzed with Origin 6.0 and Microsoft Office Excel 2007 software. A total of 248 radical cystectomies with 8,432 LNs were reviewed. A total of 60 (24 %) cases, with 274 positive LNs out of the 1,982 total (13.8 %), were identified with a male to female ratio of 6.5:1 (52 male, 8 female patients). The average number of LNs examined in each case was 33.0?±?20.9 (range 5–112). The average number of positive LNs identified in each case was 4.5?±?4.8 (range 1–26). Among all of the LNs, the hypogastric/obturator (internal iliac) LNs were the most commonly submitted (35.2 %) and also yielded the highest number of positive LNs (46.0 %). On average, for cases staged pN1 and pN2, there was one positive LN per 17.8 and 8.9 LNs examined from the primary drainage LNs, respectively. For pN3 cases, one out of 4.4 secondary drainage LNs was found to be positive. Similarly, one out of 4.0 distant LNs was found to be positive in cases with pM1 staging. Our study suggests that, on average, 23 LNs (including 18 primary drainage LNs and five secondary drainage LNs) should be submitted for optimal pN staging. For adequate pM1 staging, an average of four distal LNs should be evaluated. In total, an average of 27 LNs (23 for pN staging and 4 for pM staging) should be examined in radical cystectomy specimens. We also propose to stratify the number of positive LNs according to the drainage area.     

荧光成像技术联合美蓝在乳腺癌术中探寻前哨淋巴结的应用价值

目的:探讨采用荧光成像技术联合美蓝示踪剂在女性乳腺癌手术治疗中探寻前哨淋巴结的临床应用价值.方法:选取我院收治的150例常规检测为原发性乳腺癌患者,随机分为3组,每组各50例,分别接受联合注射吲哚菁绿(indocyanine green,ICG)及美蓝(联合组)、单独注射ICG(ICG组)和单独注射美蓝(美蓝组)行前哨淋巴结活检手术(sentinel lymph node biopsy,SLNB),后将探寻的前哨淋巴结取出进行冰冻病理检查或常规石蜡病理检查.结果:联合组患者体外淋巴管显影率为94%(47/50),剩余3例有2例为切开后淋巴结显影,淋巴结荧光显影率为92%(46/50).联合组前哨淋巴结(sentinel lymph nodes,SLNs)的总检出率98%(49/50),检出SLNs数量为180枚,其中阳性患者10例(20.41%);ICG组的总检出率为90%(45/50),检出数量为158枚,阳性患者8例(17.78%);美蓝组的总检出率为88%(44/50),检出数量为150枚,阳性患者7例(15.91%);联合组相关观察指标均要优于ICG组和美蓝组.结论:ICG联合美蓝示踪法,相比单独注射ICG或美蓝,能明显提高乳腺癌患者前哨淋巴结的检出率和检出数量,为乳腺癌患者手术方案的选择提供更准确的指导.     

Ex vivo intra-arterial methylene blue injection in the operation theater may improve the detection of lymph node metastases in colorectal cancer

IntroductionLymph node (LN) assessment after colorectal cancer resection is fundamentally important for therapeutic and prognostic reasons. LN positivity is an indication for adjuvant treatment. This study aimed to investigate whether immediate postoperative intra-arterial methylene blue (MB) injection (MBI) into colorectal cancer specimens by a surgeon in the operating room could improve the rate of total LN and metastatic LN recovery for pathological examination.Materials and methodsSeventy-three consecutive patients prospectively enrolled between January 2011 and December 2013 were assigned to the methylene blue (MB)-stained group and compared with 107 controls in the unstained group.ResultsThe median number and range values of metastatic LNs, the number of LNs <0.5 cm, the total number of LNs harvested, and the number of cases with LN metastasis were significantly different between the MB-stained and MB-unstained groups (p = 0.016, p = 0.010, p = 0.025, and p = 0.006 respectively).ConclusionsImmediate MBI (fresh, unfixed samples) by a surgeon in the operating room may result in a significant increase in the number of metastatic LNs diagnosed and the number of cases with positive LNs. Shifting of the injection from the pathology laboratory to the operation theater would be a good alternative whenever the operation theater is not the area located as the pathology department.     

Initial results of imaging melanoma metastasis in resected human lymph nodes using photoacoustic computed tomography

The pathological status of the sentinel lymph node is important for accurate melanoma staging, ascertaining prognosis and planning treatment. The standard procedure involves biopsy of the node and histopathological assessment of its status. Drawbacks of this examination include a finite sampling of the node with the likelihood of missing metastases, and a significant time-lag before histopathological results are available to the surgeon. We studied the applicability of photoacoustic computed tomographic imaging as an intraoperative modality for examining the status of resected human sentinel lymph nodes. We first applied the technique to image ex vivo pig lymph nodes carrying metastases-simulating melanoma cells using multiple wavelengths. The experience gained was applied to image a suspect human lymph node. We validated the photoacoustic imaging results by comparing a reconstructed slice with a histopathological section through the node. Our results suggest that photoacoustics has the potential to develop into an intraoperative imaging method to detect melanoma metastases in sentinel lymph nodes.     

Genomic alterations in primary breast cancers compared with their sentinel and more distal lymph node metastases: An aCGH study

Metastatic potential of breast cancer may be associated with specific genomic alterations and the earliest metastases are likely to be found in the sentinel lymph nodes (SLN). Using array comparative genomic hybridization (aCGH), we compared the genomes of primary breast invasive duct carcinomas (IDCs), their sentinel and more distal lymph node metastases, and IDCs without nodal metastasis. Thirty‐three samples from 22 patients with IDC were subjected to aCGH: 8 IDC samples from patients without lymph node metastasis, 11 IDCs associated with SLN metastases out of which 7 had paired samples of metastases, and 14 samples of lymph node metastases out of which 8 were sentinel‐distal pairs from 4 patients. aCGH data were analyzed by correlation of genomic profiles, cluster analysis, segmentation, and peak identification. Quantitative real‐time PCR was used for data validation. We observed high genomic similarity between primary tumors and their nodal metastases as well as between metastases to the sentinel and distal lymph nodes. Several recurrent alterations were detected preferentially in IDC associated with SLN metastases compared to IDCs without metastasis. Amplification within the 17q24.1‐24.2(59.96–62.76 Mb) region was associated with presence of sentinel or distal lymph node metastases; larger tumor size and higher histological grade. In our samples, there were genomic events associated with metastatic progression, which could be detected in both primary tumors and LN metastases. Gain on 17q24.1‐24.2 is a candidate region for further testing as a predictor of nodal metastasis. © 2009 Wiley‐Liss, Inc.     

Keratin immunohistochemistry does not contribute to correct lymph node staging in patients with invasive lobular carcinoma

Studies suggest that immunohistochemistry improves rate of detecting sentinel lymph node metastases and is needed for adequate staging in invasive lobular carcinoma. Our study evaluates the use of cytokeratin immunohistochemistry in detecting sentinel lymph node metastases and its effect on staging patients with invasive lobular carcinoma. Material from 76 patients with invasive lobular carcinoma was reviewed. Cytokeratin immunostaining was performed on negative nodes, and deposits were classified as macrometastasis (>2.0 mm), micrometastasis (>0.2-2 mm), or isolated tumor cells (相似文献   

Towards reasonable workload in diagnosis of sentinel lymph nodes: comparison of two frozen section methods

AIMS: To compare two methods of histological assessment with intraoperative diagnosis of sentinel node metastases in breast cancer. METHODS AND RESULTS: A total of 204 consecutive breast cancer cases with lymphatic mapping, sentinel node biopsy and intraoperative diagnosis were included. The sentinel nodes in the first 102 cases (method A) were bisected and serially sectioned. In the other 102 cases (method B) the nodes were sliced thinly with a razor blade. All 1-1.5 mm thick slices were mounted on prechilled mounting medium on frozen section buttons. Cytological imprints were also made of the attached tissue slices. Postoperative diagnosis of sentinel lymph node metatases was taken as gold standard. Sentinel node metastases were found in 28 (27%) cases in group A and in 42 (40%) cases in group B (P = 0.05). The median size of the sentinel node metastases was 4.3 mm in group A and 3.3 mm in group B (P < 0.05). CONCLUSION: Method B finds more and smaller metastases and takes less time and effort in the laboratory. When using method A, many small metastases are not detected at all.     

Tumor and lymph node lymphangiogenesis--impact on cancer metastasis

The extent of lymph node (LN) metastasis is a major determinant for the staging and the prognosis of most human malignancies and often guides therapeutic decisions. Although the clinical significance of LN involvement is well documented, little has been known about the molecular mechanisms that promote tumor spread via lymphatic vessels to sentinel and distal LN and beyond. However, recent discoveries have identified novel lymphatic-specific markers, and the newly discovered lymphangiogenesis factors vascular endothelial growth factor-C (VEGF-C) and VEGF-D were found to promote tumor-associated lymphatic vessel growth in mouse tumor models, leading to enhanced tumor spread to sentinel LN. Our recent findings indicate that VEGF-A also acts as a potent tumor lymphangiogenesis factor that promotes lymphatic tumor spread. VEGF-A overexpressing primary tumors induced sentinel LN lymphangiogenesis even before metastasizing and maintained their lymphangiogenic activity after metastasis to draining LN. Our recent studies showed that primary human melanomas that later metastasized were characterized by increased lymphangiogenesis and that the degree of tumor lymphangiogenesis can serve as a novel predictor of LN metastasis and overall patient survival, independently of tumor thickness. Tumor lymphangiogenesis also significantly predicted the presence of sentinel LN metastases at the time of surgical excision of the primary melanoma. Together, these findings suggest that tumor lymphangiogenesis actively contributes to cancer dissemination, that blockade of lymphatic vessel growth might inhibit tumor metastasis to LN, and that the extent of tumor-associated lymphangiogenesis could serve as a novel, prognostic parameter for the metastatic risk of human cancers.     

Comparison of molecular determinants of angiogenesis and lymphangiogenesis in lymph node metastases and in primary tumours of patients with breast cancer

Angiogenesis and lymphangiogenesis are complex processes, driven by multiple factors. In primary breast tumours (PTs), VEGFA, -C and -D are the most important (lymph)angiogenic factors. The induction of lymphangiogenesis in axillary lymph node (LN) metastases of patients with breast cancer was described recently. To compare the molecular determinants of (lymph)angiogenesis in LN metastases and PTs of breast cancer patients, RNA was isolated from formalin-fixed, paraffin-embedded tissue sections of a metastatically involved and uninvolved LN and the PT from 26 lymph node-positive patients. The expression of 12 (lymph)angiogenic markers was measured by qRT-PCR. Expression was correlated with tumour cell proliferation, angiogenesis and lymphangiogenesis, quantified by tumour cell proliferation fraction (TCP%) and (lymphatic) endothelial cell proliferation fraction [(L)ECP%]. TCP%, ECP% and LECP% were assessed on immunohistochemical double stains for CD34/Ki-67 and D2-40/Ki-67, respectively. In involved LNs, the relative gene expression levels of PROX1 (p < 0.001) and FGF2 (p = 0.008) were decreased and the expression levels of VEGFA (p = 0.01) and PDGFB (p = 0.002) were increased compared to uninvolved LNs. The expression of most markers was increased in PTs compared to involved LNs. In metastatically involved LNs, the expression of VEGFA correlated with ECP% (r = 0.54, p = 0.009) and LECP% (r = 0.76, p < 0.001). In PTs, VEGFA correlated only with ECP% (r = 0.74, p < 0.001). VEGFD correlated with peritumoural LECP% (r = 0.61, p = 0.001) and with VEGFC (r = 0.78, p < 0.001). Linear regression analysis confirmed the expression of VEGFA as an independent predictor of ECP% in both PTs and LN metastases and of LECP% in LN metastases. The expression of VEGFD, but not of VEGFA, independently predicted peritumoural LECP% in PTs. Our results confirm existing data that, in PTs, angiogenesis and lymphangiogenesis are respectively driven by VEGFA and VEGFD. In contrast, in LN metastases, both processes seem to be driven by VEGFA. Lymphangiogenesis in PTs and in LN metastases might thus be driven by different factors.     

Evaluation of sentinel lymph nodes in breast cancer

Sentinel lymph node biopsy is an accurate method for the detection of axillary metastases in cases of breast carcinoma and is of value as a replacement for axillary dissection. There is variation, however, in the methods and protocols used for the histopathological evaluation of sentinel lymph nodes, standardisation of which will be required if results of sentinel lymph node analysis are to be used to stratify patients into prognostic groups. The significance of micrometastases, isolated tumour cells (ITCs) and the value of immunohistochemistry are also matters for further definition. In this Expert Opinion we present reviews from two authors, providing American and European perspectives on the approach to sentinel lymph node evaluation.     

Histopathological study of lymph node lesions in the acute phase of Kawasaki disease

Aims: To review the histopathological features of cervical LNs, and to clarify the changes in extracervical LNs, in acute Kawasaki disease (KD). Methods and results: The samples were obtained from 33 patients with acute‐phase KD. We divided the LNs into those in the neck (n = 23) and those located elsewhere (n = 26), and investigated them histologically. Changes occur not only in the cervical region, but also in LNs throughout the body. Most lymphadenopathy is non‐specific, caused by sinus expansion and paracortical zone enlargement, but there are also necrotic lesions of various sizes that can be surmised to result from ischaemic changes in some LNs. Necrotic foci start to develop immediately below the capsule, and are accompanied by fibrin thrombi in the small vessels and perivascular nuclear debris. Especially in the case of cervical LNs with necrosis, a high degree of non‐purulent inflammation develops in the LN capsule and surrounding connective tissue. Conclusions: In addition to lymphadenopathy with necrosis, KD should be suspected if there is non‐purulent inflammation of the LN capsule and/or surrounding connective tissue featuring mainly monocytes/macrophages.     

Key architectural changes in tumor-negative lymph nodes from metastatic-free oral cancer patients are valuable prognostic factors

Regional lymph node (LN) metastasis in oral cancer patients is the most significant grave prognostic factor. We evaluated the relationship between clinical outcomes and different histopathological changes in tumor-negative LNs (LN0) selected from neck dissections without metastatic disease (pN0). A total of 435 LN0 selected from pN0 neck dissections (up to three nodes in each level) were scored for histopathological parameters of LN areas, capsule thickness, subcapsular and medullary sinus ectasia, lobular architecture and percent of cortical reactive follicles. These were compared to 328 LN0 selected from neck dissections with metastases (pN+) after exclusion of metastatic LNs. Data were presented by maximum scores of each parameter in I–III (close) and in IV–V (distant) levels. Limited data from level V and regression analyses inferred that the values in level IV represented the worst changes for most patients. Cox proportional hazard regression on each parameter in close and distant levels demonstrated that capsule thickness, number of lobules and percent of reactive follicles were significantly associated with time to death from disease. The higher the change in distant levels, the shorter the time to death, while the higher the change in close levels (given a stable change in distant levels), the longer the time to death. After adjustment for gender, age and location, only the effect of the percent of reactive follicles retained their significant effect. Logistic regression of metastases demonstrated that all parameters except for percent of reactive follicles were significantly associated with risk of metastases, with differences between close and distant levels similar to those found for time to death. After adjustment for gender, age and location, only the area and number of lobes retained their significance. The findings of this study suggested that selective histopathological changes in tumor-negative LNs in metastatic-free patients provide new valuable prognostic parameters.     

Anatomo-pathologic study of sentinel lymph nodes in melanoma. Analysis of 200 cases

Pathologic evaluation of sentinel lymph node represents a new technique for managing high-risk primary melanoma. We examined the sentinel lymph node biopsies of 200 patients affected by primary melanomas of trunk, limbs, head and neck, who had been operated at "M. Bufalini" Hospital between April 1996 and July 1998. The lymphatic mapping has been performed through the preoperative intradermal injection of vital blue dye and technetium-labelled albumin. 319 sentinel lymph nodes were harvested and the 11.3% (15% of patients) were positive for melanoma metastases. No metastases were found in melanomas < or = 1 mm. The percentage of positive sentinel lymph nodes in patients with melanomas > 1 mm in thickness was 16.3% (22% of patients). In 5 cases (2.5%) nodal nevi were found, 1 of which was associated with micrometastasis. All 30 patients with positive sentinel lymph nodes underwent regional lymph node dissection and 555 lymph nodes were harvested. Melanoma metastases were found in only 7 patients, in 31 lymph nodes. The procedure of SLN detection and biopsy is a feasible surgical approach to melanoma patients. It is extremely useful in finding early metastases and in effective pathologic staging. As a consequence of the very low incidence of metastases in the sentinel lymph nodes of patients with thin melanomas, we suggest the sentinel lymph node mapping should be offered to patients with primary melanomas at least 1 mm in depth.