No non-sentinel node involvement in melanoma patients with limited Breslow thickness and low sentinel node tumour load

Bogenrieder T, van Dijk M R, Blokx W A M, Ramrath K, Seldenrijk K, Stolz W & van Diest P J
(2011) Histopathology 59 , 318–326 No non‐sentinel node involvement in melanoma patients with limited Breslow thickness and low sentinel node tumour load Aims: Most melanoma patients with a positive sentinel node (SN) undergo completion lymph node dissection and frequently experience associated morbidity. However, only 10–30% of SN‐positive patients have further lymph node metastases. The aim of the present study was to predict the absence of non‐SN metastases in a multicentre study of patients with a positive SN based on primary melanoma features and SN tumour load. Methods and results: Of 70 SN positive patients, 18 had non‐SN metastases. Penetrative depth of metastatic cells into the SN and SN tumour load was assessed by morphometry. None of the 14 patients (20%) with a Breslow thickness <2.0 mm and an SN tumour load <0.2 mm² had non‐SN metastases. Similarly, none of the 15 patients (21%) with a Breslow thickness <2.0 mm and SN penetrative depth <600 μm had non‐SN metastases. Lastly, none of the 14 patients (20%) with a Breslow thickness <2.0 mm and a diameter of the largest SN deposit <500 μm had non‐SN metastases. Conclusions: A combination of limited Breslow thickness and low SN tumour load predicts absence of non‐SN metastases in melanoma patients with a positive SN with high accuracy. We propose that this subgroup may be spared completion lymph node dissection.     

Sentinel lymph nodes in cutaneous melanoma: the experience in the Florence area

In the period 1997-2001, 466 sentinel lymph nodes from 342 lymphatic basins in 322 melanoma patients were examined at the Health Unit of Florence. The lymphatic mapping was performed through pre-operative lymphoscintigraphy using technetium-labelled nano-colloid, intradermal injections of vital blue dye and intra-operative gamma-probe. The examined patients were 182 females and 140 males. Sentinel lymph node was one in 65.2% of cases; two sentinel lymph nodes were detected in 27% of cases and more than 2 sentinel nodes were detected in 7.8% of cases. Melanoma metastases in one or more sentinel lymph nodes were found in 61/322 patients (18.9%). Lymphatic basins resulted to be involved by melanoma metastases were 64/342 (18.7%); sentinel lymph nodes containing metastatic melanoma deposits were 73/466 (15.6%). No metastasis was found in patients with melanoma thickness < or = 1 mm. One or more positive sentinel lymph nodes were found in 7.5% of patients with melanoma thickness > 1.00 and < or = 1.50 mm, in 27.7% of patients with melanoma > 1.50 and < or = 3.00 mm, in 38.2% of patients with melanoma > 3.00 and < or = 4.00, and in 60.7% of patients with melanoma > 4.00 mm. Frozen section analysis of sentinel lymph nodes, performed in 59/61 patients with nodal metastases, detected nodal involvement in 21 patients (35.6%). Metastases were identified by routine hematoxylin-eosin staining in 57/64 positive lymphatic basins; in 7 cases (11%) metastases were detected by immunohistochemical stainings (S100 and HMB-45). A nodal nevus was found in 3/466 sentinel lymph nodes (0.6%). Our data are analyzed and compared to previously data of the literature. The value of frozen section analysis and the major problems in the diagnosis of melanoma micrometastases in sentinel lymph nodes are discussed. The importance of the sentinel node biopsy for the detection of occult metastases and for the correct staging of melanoma patients are stressed, according to the new TNM melanoma classification.     

Assessment of sentinel lymph nodes for breast cancer

Sentinel lymph node biopsy is standard of care for assessment of lymph node stage in early breast cancer in patients with clinically negative nodes. The limited clinical significance of low volume axillary metastatic disease has led to changes in surgical management of the axilla with a shift away from routine axillary lymph node dissection if the sentinel lymph node is found to contain metastatic tumour. This has led to a decrease in the use of intraoperative assessment of sentinel nodes. Specimen handling and histological assessment of sentinel lymph nodes is described, with the emphasis on identification of macrometastatic disease defined as metastases greater than 2 mm. Routine levels and/or cytokeratin immunohistochemistry is not recommended. The increasing use of neoadjuvant chemotherapy and growing evidence that sentinel lymph node biopsy is safe and accurate in this setting, including in patients with proven node positive disease, has resulted in new challenges in the interpretation of these specimens.     

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.     

The value of cytokeratin immunohistochemistry in the evaluation of axillary sentinel lymph nodes in patients with lobular breast carcinoma

BACKGROUND: Cytokeratin immunohistochemistry (IHC) reveals a higher rate of occult lymph node metastases among lobular carcinomas than among ductal breast cancers. IHC is widely used but is seldom recommended for the evaluation of sentinel lymph nodes in breast cancer patients. Objective: To assess the value of cytokeratin IHC for the detection of metastases in sentinel lymph nodes of patients with invasive lobular carcinoma. METHODS: The value of IHC, the types of metastasis found by this method, and the involvement of non-sentinel lymph nodes were analysed in a multi-institutional cohort of 449 patients with lobular breast carcinoma, staged by sentinel lymph node biopsy and routine assessment of the sentinel lymph nodes by IHC when multilevel haematoxylin and eosin staining revealed no metastasis. RESULTS: 189 patients (42%) had some type of sentinel node involvement, the frequency of this increasing with increasing tumour size. IHC was needed for identification of 65 of these cases: 17 of 19 isolated tumour cells, 40 of 64 micrometastases, and 8 of 106 larger metastases were detected by this means. Non-sentinel-node involvement was noted in 66 of 161 cases undergoing axillary dissection. Although isolated tumour cells were not associated with further lymph node involvement, sentinel node positivity detected by IHC was associated with further nodal metastases in 12 of 50 cases (0.24), a proportion that is higher than previously reported for breast cancer in general. CONCLUSIONS: IHC is recommended for the evaluation of sentinel nodes from patients with lobular breast carcinoma, as the micrometastases or larger metastases demonstrated by this method are often associated with a further metastatic nodal load.     

Histopathological patterns of melanoma metastases in sentinel lymph nodes

AIMS: Sentinel lymph node biopsy (SLNB) is an important component in the staging and treatment of cutaneous melanoma (CM). The medical literature provides only limited information regarding melanoma sentinel lymph node (SLN) histology. This report details the specific histological patterns of melanoma metastases in sentinel lymph nodes (SLNs) and highlights some key factors in evaluating SLNs for melanoma. METHODS: From 281 SLNB cases between June 1998 and May 2002, 79 consecutive cases of SLN biopsies positive for metastases from CM were retrospectively reviewed. The important characteristics of the SLNs and the metastatic foci are described. RESULTS: The median size of positive SLNs was 17 mm (range, 5-38). SLNs had a median of two metastatic foci (range, 1-11), with the largest foci being a median of 1.1 mm in size (range, 0.05-24). S-100 and HMB-45 staining was positive in 100% and 92% of the detected metastatic foci, respectively. The metastatic melanoma cells were epithelioid, spindled, and mixed in 86%, 5%, and 9% of cases. Metastatic foci were most often (86%) found in the subcapsular region of the SLN. Benign naevic cells were found coexisting in 14% of positive SLNs. CONCLUSIONS: Staining for S100 is more sensitive than HMB-45 (100% v 92%), but HMB-45 staining helped to distinguish benign naevic cells from melanoma. The subcapsular region was crucial in SLN evaluation, because it contained the metastases in 86% of cases. Evaluation of the subcapsular space should not be compromised by cautery artefacts or incomplete excision of the SLN.     

Specificity of tyrosinase and HMB45 PCR in the detection of melanoma metastases in sentinel lymph node biopsies

AIMS: Sentinel lymph node biopsy is an increasingly established procedure in the primary staging of high-risk melanoma patients. However, the laboratory evaluation of sentinel lymph node biopsies is a matter of controversy. The aim of this study was to determine the specificity of polymerase chain reaction (PCR) techniques for the evaluation of lymph nodes with regard to melanoma metastases in comparison with histology and immunohistology. METHODS AND RESULTS: Sentinel lymph nodes (n = 41) from 29 melanoma patients and 29 lymph nodes from 27 patients without melanoma were analysed by histology (H&E) and immunohistology (Melan A, HMB45). cDNA of these lymph nodes was subjected to LightCycler PCR amplification using primers specific for tyrosinase and HMB45. Two melanoma sentinel lymph nodes contained naevus cells by histology and immunohistology and were therefore excluded from further evaluation. Eight (20.5%) of the remaining 39 melanoma sentinel lymph nodes were positive by histology and immunohistology and tyrosinase PCR, 15.4% (6/39) were positive only by tyrosinase PCR, 2.6% (1/39) were positive only by histology and immunohistology. HMB45 PCR revealed positive results in 7.7% (3/39) sentinel lymph nodes, which were also positive by tyrosinase PCR and histology and immunohistology. Of non-melanoma lymph nodes 13.8% (4/29) and 14.8% (4/27) of non-melanoma patients were positive by tyrosinase PCR but negative by histology and immunohistology and HMB45 PCR. Thus, tyrosinase PCR had a specificity of only 85.2%. CONCLUSIONS: The specificity of tyrosinase PCR and the sensitivity of HMB45 PCR are too low to recommend these PCR examinations for the guidance of therapy, in particular complete regional lymph node dissection.     

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   

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.     

Can Melan-A replace S-100 and HMB-45 in the evaluation of sentinel lymph nodes from patients with malignant melanoma?

The sentinel lymph node (SLN) biopsy has become an increasingly important procedure used in the primary staging of malignant melanoma. However, micrometastases in a lymph node can be easily missed on routine H&E-stained sections. Therefore, S-100 and HMB-45 IHC stains are standardly performed on grossly negative SLNs for detection of metastatic melanoma. Each of these IHC markers, however, is not ideal. The authors investigated whether the newer IHC marker Melan-A would improve the detection of metastatic melanoma in SLN biopsies. Forty lymph nodes previously diagnosed with metastatic melanoma were retrospectively evaluated for S-100, HMB-45, and Melan-A expression. In addition, 42 SLN biopsies for metastatic melanoma detection were prospectively collected and evaluated for S-100, HMB-45, and Melan-A expression. All lymph nodes with metastatic melanoma from the retrospective study demonstrated S-100 reactivity. Five of the lymph nodes with metastatic melanoma from the retrospective study failed to express either HMB-45 or Melan-A, all of which displayed a desmoplastic morphology. One of the metastases positive for S-100 and HMB-45 failed to show reactivity with Melan-A (3%). The prospective study found 10 lymph nodes from 42 cases to be positive for metastatic melanoma, which were positive for S-100 (100%). Nine of the involved lymph nodes were positive for HMB-45(90%), and nine were positive for Melan-A (90%). Melan-A, although very specific, cannot replace the use of S-100 and HMB-45 for the detection of metastatic melanoma in SLNs. It can, however, substitute for HMB-45 with equally good results.     

The influence of nodal size on the staging of colorectal carcinomas

AIMS: The reliable identification of node negative colorectal carcinomas (CRCs) has often been linked to the histological examination of a minimum number of lymph nodes. The sizes of the lymph nodes, their metastatic status, and their number were investigated to establish whether these parameters are related, and whether their relation could help in determining the adequacy of staging. METHODS: One thousand three hundred and thirty four negative lymph nodes, 189 metastatic lymph nodes, and 43 pericolonic/perirectal tumour deposits measuring > or = 3 mm from 60 node positive and from 63 node negative patients with CRC were assessed for size. RESULTS: The mean size (SD) of these structures was 4.5 (2.7) mm. The lymph nodes were significantly larger in the CRCs with metastatic nodes (4.7 v 4.3 mm). Involved nodes were significantly larger than negative nodes (6.3 v 4.2 mm), despite the fact that the largest node was < or = 5 mm in one third of node positive CRCs. The examination of the seven largest nodes could have adequately staged 97% of node positive CRCs and 98% of all CRCs. CONCLUSIONS: The nodal staging of CRCs is dependent not only on the number of lymph nodes investigated, but also on qualitative features of the lymph nodes assessed, including their size. Lymph nodes are not equivalent and any study neglecting this fact will give grounds for error in the recommendation of a minimum number of nodes for the reliable determination of node negative CRCs. Although pathologists should aim to recover all nodes, a negative nodal status based on only seven nodes can be reliable.     

Reliability of intraoperative frozen section and imprint cytological investigation of sentinel lymph nodes in breast cancer

AIMS: The sentinel lymph node procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative sentinel node (SN) predicts the absence of tumour metastases in the other regional lymph nodes with high accuracy. This means that in the case of a negative SN, regional lymph node dissection is no longer necessary. Besides saving costs, this will prevent many side-effects of lymph node dissection. The aim of this study was to evaluate the reliability of intraoperative cytological and frozen section investigation of the SN to detect metastases. This would allow the axillary lymph node dissection to be performed in the same session as the SN procedure and the excision of the primary tumour in case of a positive SN. METHODS AND RESULTS: Seventy-four SNs were detected by gamma probe detection of nanocolloid and visual localization of Patent Blue accumulations in 54 women with stage T1-2N0M0 invasive breast cancer. The identified SN were immediately investigated by frozen section and imprint cytological investigation. Diagnoses were confirmed on the paraffin material, and in case of negative frozen section and paraffin haematoxylin and eosin sections, skip sections and immunohistochemistry were performed. Thirty-one SNs (42%) contained metastases, of which 27 were detected by the frozen section procedure (sensitivity 87%). There were no false positives (specificity 100%). The sensitivity of the imprints was 62% with a specificity of 100%. When evaluating the data per patient, for the frozen section procedure the sensitivity was 91% and the specificity 100%, and for the imprints, the sensitivity was 63% and the specificity 100%. There were no SNs in which the imprints showed metastases and the frozen section did not. CONCLUSIONS: Intraoperative frozen section analysis is a reliable procedure by which a high percentage of sentinel lymph node metastases can be detected in breast cancer patients without false positive results. This allows the surgeon to perform an immediate axillary lymph node dissection in case of positive SNs. In up to 10% of cases, the final paraffin sections will reveal micrometastases that were not detected by the frozen section, and in these patients axillary lymph node dissection will have to be performed in a second session. The imprint method is significantly less sensitive than the frozen section but may be used as an alternative when frozen section is not possible.     

Iatrogenically false positive sentinel lymph nodes in breast cancer: Methods of recognition and evaluation

With the introduction of sentinel lymph node (SLN) biopsy as a standard procedure for staging clinically node negative breast cancer patients, meticulous pathologic evaluation of SLNs by serial sections and/or immunohistochemistry for cytokeratins has become commonplace in order to detect small volume metastases (isolated tumor cells and micrometastases). This practice has also brought to the fore the concept of iatrogenically false positive sentinel nodes secondary to epithelial displacement produced largely by preoperative needling procedures. While this concept is well described in the clinical and pathologic literature, it is, in our experience, still under-recognized, with such lymph nodes frequently incorrectly diagnosed as harboring true metastases, possibly resulting in unwarranted further surgery and/or chemotherapy. This review discusses the concept of displaced epithelium in the histologic evaluation of breast surgical specimens and provides a stepwise approach to the correct identification of iatrogenically transported displaced epithelial cells in sentinel lymph nodes.     

Impact of sentinel lymphadenectomy on survival in a murine model of melanoma

Lymphatic mapping and sentinel lymph node biopsy—also termed sentinel lymphadenectomy (SL)—has become a standard of care for patients with primary invasive cutaneous melanoma. This technique has been shown to provide accurate information about the disease status of the regional lymph node basins at risk for metastasis, provide prognostic information, and provide durable regional lymph node control. The potential survival benefit afforded to patients undergoing SL is controversial. Central to this controversy is whether metastasis to regional lymph nodes occurs independent of or prior to widespread hematogenous dissemination. A related area of uncertainty is whether tumor cells residing within regional lymph nodes have increased metastatic potential. We have used a murine model of primary invasive cutaneous melanoma based on injection of B16-BL6 melanoma cells into the pinna to address two questions: (1) does SL plus wide excision of the primary tumor result in a survival advantage over wide excision alone; and (2) do melanoma cells growing within lymph nodes produce a higher incidence of hematogenous metastases than do cells growing at the primary tumor site? We found that SL significantly improved the survival of mice with small primary tumors. We found no difference in the incidence of lung metastases produced by B16-BL6 melanoma cells growing exclusively within regional lymph nodes and cells growing within the pinna.     

Prediction of metastatic melanoma in nonsentinel nodes and clinical outcome based on the primary melanoma and the sentinel node.

Lymphatic mapping and sentinel node biopsy are well-established techniques for staging and managing patients with melanoma, breast cancer and other malignancies that spread initially to the regional lymph nodes. Identification of tumor in the sentinel node is the most precise staging technique currently available. The sentinel node is the site of metastatic melanoma in approximately 20% of melanoma patients and if tumor is present in the sentinel node it is customary to perform a complete dissection of the lymph nodes of the affected nodal basin. This may be overtreatment for some patients as tumor is identified in the nonsentinel nodes of only one-third of sentinel node-positive melanoma patients treated by completion lymphadenectomy. If it were possible accurately to identify the minority of patients with tumor in the nonsentinel nodes, the patients most likely to benefit from lymphadenectomy, the remaining patients could be spared a potentially morbid operation that is unlikely to confer clinical advantage. In 90 patients with a melanoma-positive sentinel node, who subsequently had a completion lymphadenectomy, we evaluated and compared the capacity of characteristics of the primary melanoma and of the sentinel node to predict individuals likely to have tumor in nonsentinel nodes. We assessed the Breslow thickness of the primary, the amount of tumor in the sentinel node (relative tumor area) and, as an index of immune modulation of the sentinel node, the density of dendritic leukocytes in the nodal paracortex. The relative area of tumor in the sentinel node and Breslow thickness of the primary melanoma most accurately predicted the presence of tumor in the nonsentinel nodes (P=0.0001 in both cases-Wilcoxon rank sums). The presence of melanoma in the nonsentinel nodes was also predicted by the density of dendritic leukocytes in the paracortex (P=0.008-Wilcoxon rank sums). These three observations assessed alone and in combination predict the presence of tumor in the nonsentinel nodes with high accuracy. The same characteristics also significantly correlated with tumor recurrence (tumor burden, P=0.0001, Breslow, P=0.0001 and dendritic cell density, P=0.0007) and death from melanoma (tumor burden, P=0.0001, Breslow, P=0.0001 and dendritic cell density, P=0.0026).     

Pathology of sentinel lymph nodes for melanoma

As a concept sentinel lymph node biopsy seems attractive in that it attempts to identify the first lymph node, rather than the nearest node, draining a particular anatomic area where a tumour has arisen. Pathological assessment can then indicate whether metastases are present and the procedure is either a strong prognostic indicator or possibly therapeutic in itself. These comments apply to any tumour type, but with melanoma the pathological procedure is more problematic and any benefits above prognosis and staging are not universally accepted. The procedure does give accurate staging without the extra morbidity of regional node dissection and many patients gain psychological support from the information gained.