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.     

Micromorphometric features of positive sentinel lymph nodes predict involvement of nonsentinel nodes in patients with melanoma

The aim of the present study was to determine whether micromorphometric features of positive sentinel lymph nodes (SLNs) from patients with melanoma are useful for predicting further nodal involvement in completion lymph node dissection (CLND) specimens. Of 986 patients with melanoma undergoing SLN biopsy between March 1992 and February 2001, 175 (17.7%) had at least 1 positive SLN and 140 had subsequent CLND specimens available for review. Further nodal involvement in CLND specimens was present in 24 (17.1%) of 140 patients. Of 8 micromorphometric features of the SLNs that were assessed, the presence of metastases in CLND specimens was correlated significantly with a tumor penetrative depth (maximum distance of melanoma cells from the inner margin of the SLN capsule) of more than 2 mm (P < .05), a deposit size of more than 10 mm2 (P < .01), the presence of melanoma cells in perinodal lymphatic vessels (P < .01), and the effacement of nodal architecture by metastatic melanoma cells (P < .05). Our results indicate that some morphologic features of melanoma metastases in SLNs predict the likelihood of further nodal involvement in CLND specimens.     

Nodal melanocytic nevi in sentinel lymph nodes. Correlation with melanoma-associated cutaneous nevi

Melanocytic nevi occurring in lymph nodes create diagnostic difficulty by mimicking metastases. Few studies describe nodal nevi in sentinel lymph nodes (SLNs) excised for melanoma. We evaluated 72 cases in which patients had undergone SLN biopsy for melanoma. Lymph nodes and cutaneous melanomas were evaluated according to a standard protocol. Nodal nevi were identified in 8 patients (11%). Of these, 6 (75%) had an associated cutaneous nevus (P = .006). Of 21 patients with an associated nevus, 4 (19%) with nodal nevi had a cutaneous nevus with congenital features (P = .01). The incidence of nodal nevus correlated with a Breslow thickness greater than 2.5 mm (P = .02). Nevi were not seen in non-SLNs. Nodal nevi appear more frequently in patients with melanoma-associated cutaneous nevi, particularly if congenital features are present. The increased frequency of nodal nevi in SLNs relative to non-SLNs suggests an etiology of mechanical transport of nevus cells.     

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.     

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.     

Anatomical classification of breast sentinel lymph nodes using computed tomography–lymphography

To evaluate the anatomical classification and location of breast sentinel lymph nodes, preoperative computed tomography–lymphography examinations were retrospectively reviewed for sentinel lymph nodes in 464 cases clinically diagnosed with node-negative breast cancer between July 2007 and June 2016. Anatomical classification was performed based on the numbers of lymphatic routes and sentinel lymph nodes, the flow direction of lymphatic routes, and the location of sentinel lymph nodes. Of the 464 cases reviewed, anatomical classification could be performed in 434 (93.5 %). The largest number of cases showed single route/single sentinel lymph node (n = 296, 68.2 %), followed by multiple routes/multiple sentinel lymph nodes (n = 59, 13.6 %), single route/multiple sentinel lymph nodes (n = 53, 12.2 %), and multiple routes/single sentinel lymph node (n = 26, 6.0 %). Classification based on the flow direction of lymphatic routes showed that 429 cases (98.8 %) had outward flow on the superficial fascia toward axillary lymph nodes, whereas classification based on the height of sentinel lymph nodes showed that 323 cases (74.4 %) belonged to the upper pectoral group of axillary lymph nodes. There was wide variation in the number of lymphatic routes and their branching patterns and in the number, location, and direction of flow of sentinel lymph nodes. It is clinically very important to preoperatively understand the anatomical morphology of lymphatic routes and sentinel lymph nodes for optimal treatment of breast cancer, and computed tomography–lymphography is suitable for this purpose.     

How morphometric analysis of metastatic load predicts the (un)usefulness of PET scanning: the case of lymph node staging in melanoma

BACKGROUND: In primary cutaneous melanoma, the sentinel node (SN) biopsy is an accurate method for the staging of the lymph nodes. Positron emission tomography (PET) has been suggested as a useful alternative. However, the sensitivity of PET may be too low to detect SN metastases, which are often small. AIM: To predict the value of PET for initial lymph node staging in melanoma based on morphometric analysis of SN metastatic load, without exposing patients to PET. MATERIALS AND METHODS: In 59 SN positive patients with melanoma, the sizes of tumour deposits in the SNs and subsequent dissection specimens were measured by morphometry and correlated with the detection limits of current and future PET scanners. RESULTS: The median tumour volume within the basin was 0.15 mm(3) (range, 0.0001-118.86). Seventy per cent of these deposits were smaller than 1 mm(3). State of the art PET scanners that have a resolution of about 5 mm would detect only 15-49% of positive basins. Logistic regression analysis revealed no pretest indicators identifying patients expected to have a positive PET. However, the SN tumour load was a significant and single predictor of the presence of PET detectable residual tumour. CONCLUSION: Morphometric analysis of metastatic load predicts that PET scanning is unable to detect most metastatic deposits in sentinel lymph nodes of patients with melanoma because the metastases are often small. Therefore, the SN biopsy remains the preferred method for initial regional staging.     

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.     

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.     

Systematic search for the best gene expression markers for melanoma micrometastasis detection

Melanoma is notorious for its high tendency to metastasize and its refractoriness to treatment thereafter. Metastasis is believed to occur mostly through the lymphatic system, and the status of sentinel lymph nodes is currently recognized as the best prognostic indicator. Unfortunately, the lymphatic metastatic process is still poorly understood and the occurrence of sentinel node metastases (micrometastases) may be underestimated. We performed genome-wide gene expression analyses of melanoma lymph node micrometastases and macrometastases, and of primary melanomas and benign naevi, to characterize the early metastatic cells molecularly and to disclose the best diagnostic markers and rational targets for therapy. Significance analysis of microarrays identified 22 over- and five under-expressed genes with > or = four-fold changes in the micrometastases. Of these genes, MLANA, TYR, MIA, ERBB3, PRAME, and SPP1 were tested as potential markers by RT-PCR and immunohistochemistry. In a prospective study of 160 patients, our graded MLANA and TYR RT-PCR analyses disclosed clinically significant metastases, as assessed by disease recurrence, better than histological and immunohistochemical examinations. These results strongly suggest the clinical implementation of quantifiable RT-PCR assays to confirm and complement the pathological examination of sentinel node metastases. Furthermore, SPP1 and PRAME proved valuable as melanoma-specific markers capable of differentiating melanoma cells from benign naevi in the sentinel lymph nodes. Importantly, these two genes may also prove to be ideal targets for drug development and therapy. Most molecular traits of the micrometastases were already present in the primary tumours, suggesting that micrometastasis to sentinel lymph nodes is a fairly non-selective process.     

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.     

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.     

Mapping Melanoma Lymphoscintigraphy Data onto a 3D Anatomically Based Model

This study describes three-dimensional (3D) visualization of two-dimensional (2D) melanoma lymphatic mapping data, to provide a framework for analysis of melanoma spread patterns and a platform for recording new lymphoscintigraphy (LS) data more accurately in 3D. Specifically, the Sydney Melanoma Unit’s LS database of over 5000 patients’ primary cutaneous melanoma sites and sentinel lymph nodes have been mapped from 2D images onto a 3D anatomically based model. Anatomically accurate model geometries were created using the Visible Human dataset, giving a bicubic finite element skin mesh and discrete sentinel lymph node model. The full dataset of 2D melanoma site coordinates, excluding the head and neck, has been transformed onto this 3D skin mesh via free-form deformation and projection techniques. Sentinel lymph nodes were mapped onto the generic lymph node model for each patient. Preliminary spatial analysis indicates that a patient with a primary melanoma on the torso around the waist (on the standardized 3D model this region is 180 mm above and 130 mm below the umbilicus) with lymphatic drainage to the left axilla or left groin, will have a 17.7% probability of dual drainage to both node fields, with 95% confidence limits between 14.5 and 21.0%.     

Evaluation using a combination of lymphatic invasion on D2-40 immunostain and depth of dermal invasion is a strong predictor for nodal metastasis in extramammary Paget's disease

In extramammary Paget's disease (EPD), lymph node metastasis occasionally occurs and nodal metastasis influences prognosis. Therefore, in the present study a predictor of nodal metastasis in EPD was examined. Surgical specimens from 54 cases of EPD in the external genitalia were examined on D2-40 immunostain. In 23 cases, dissection of the inguinal lymph nodes was performed. Dermal invasion occurred in 24 patients (44.4%). Nodal metastasis was found in seven patients who had dermal invasion >1 mm. In non-metastatic patients, three had dermal invasion <0.5 mm in depth. Lymphatic invasion was well detected on D2-40 immunostain, and invasion was found in five patients. All four patients with lymphatic invasion, in whom lymph node dissection was performed, had nodal metastasis. However, three patients with dermal invasion, who did not have lymphatic invasion, did have nodal metastasis, and the depth of invasion was >1 mm. Dermal invasion ( P  < 0.001) and lymphatic invasion according to D2-40 immunostain ( P  = 0.001) had a positive correlation with nodal metastasis. In conclusion, evaluation using a combination of lymphatic invasion according to D2-40 immunostain and depth of dermal invasion is a strong predictor of nodal metastasis in EPD.     

Tumor lymphangiogenesis predicts melanoma metastasis to sentinel lymph nodes.

Cutaneous melanoma is a common melanocytic neoplasm that can quickly metastasize to regional lymph nodes. Currently, prognosis is determined by measuring tumor thickness but more reliable markers for metastatic spread are urgently needed. We investigated whether the extent of tumor lymphangiogenesis can predict melanoma metastasis to sentinel lymph nodes. We quantified the extent of tumor lymphangiogenesis, as well as other factors, in excised primary tumors and in sentinel lymph node biopsy samples from 45 patients with primary cutaneous melanoma. The results were correlated with histological and clinical outcome. Primary melanomas from patients whose tumors had metastasized to the sentinel lymph nodes contained prominent 'hot spots' of increased lymphatic vessel density, compared to nonmetastatic tumors. Multivariate risk analysis revealed that the lymphatic vascular area of primary melanomas, an index of tumor lymphangiogenesis, was the most sensitive prognostic marker for sentinel lymph node metastasis, and was even able to more accurately predict which tumors were metastatic to sentinel lymph nodes than the currently used method of measuring tumor thickness. Highly lymphangiogenic melanomas maintained their lymphangiogenic activity after metastasis to the sentinel lymph node. The extent of tumor lymphangiogenesis is a highly sensitive (83%) and specific (89%) prognostic marker of lymph node metastasis. Assessment of lymphangiogenesis in primary melanomas may be a more effective approach than the currently used technique of measuring tumor thickness in selecting patients with early metastatic disease for aggressive therapy.     

Analysis of lymph nodal metastases in malignant melanoma using the poisson probability paradigm and Bayes rule

This article deals with and formalizes 2 notions common to the practice of pathology. The first is that the number of lymph nodes found positive for metastasis relates directly to the total number of lymph nodes examined. The second is that for any patient, there is a chance that the absence of lymph node metastases is a false-negative result. I introduce the Poisson probability density function to deal with the first notion and the Bayes probability rule to deal with the second. To illustrate the insight these 2 models provide, I apply them to data regarding lymph nodal metastases in malignant melanoma. In this preliminary study, the results of these 2 models correlate well with observed survival probabilities in patients with stage N0 melanoma and with observed rates of false-negative results in sentinel lymph node biopsy technology. With further development, the combination of these models should provide a way to estimate the probability of nodal metastasis when, in fact, none have been observed. Thus, these models might provide useful tools for evaluating patients with stage N0 malignant neoplasms.