A 3-dimensional histology computer model of malignant melanoma and its implications for digital pathology

BACKGROUND

Historically, cancer diagnoses have been made by pathologists using two-dimensional histological slides. However, with the advent of digital pathology and artificial intelligence, slides are being digitised, providing new opportunities to integrate their information. Since nature is 3-dimensional (3D), it seems intuitive to digitally reassemble the 3D structure for diagnosis.

OBJECTIVE

To develop the first human-3D-melanoma-histology-model with full data and code availability. Further, to evaluate the 3D-simulation together with experienced pathologists in the field and discuss the implications of digital 3D-models for the future of digital pathology.

METHODS

A malignant melanoma of the skin was digitised via 3 µm cuts by a slide scanner; an open-source software was then leveraged to construct the 3D model. A total of nine pathologists from four different countries with at least 10 years of experience in the histologic diagnosis of melanoma tested the model and discussed their experiences as well as implications for future pathology.

RESULTS

We successfully constructed and tested the first 3D-model of human melanoma. Based on testing, 88.9% of pathologists believe that the technology is likely to enter routine pathology within the next 10 years; advantages include a better reflectance of anatomy, 3D assessment of symmetry and the opportunity to simultaneously evaluate different tissue levels at the same time; limitations include the high consumption of tissue and a yet inferior resolution due to computational limitations.

CONCLUSIONS

3D-histology-models are promising for digital pathology of cancer and melanoma specifically, however, there are yet limitations which need to be carefully addressed.

Which melanoma patient carries a BRAF-mutation? A comparison of predictive models

Background

In patients with advanced melanoma the detection of BRAF mutations is considered mandatory before the initiation of an expensive treatment with BRAF/MEK inhibitors. Sometimes it is difficult to perform such an analysis if archival tumor tissue is not available and fresh tissue has to be collected.

Results

514 of 1170 patients (44%) carried a BRAF mutation. All models revealed age and histological subtype of melanoma as the two major predictive variables. Accuracy ranged from 0.65–0.71, being best in the random forest model. Sensitivity ranged 0.76–0.84, again best in the random forest model. Specificity was low in all models ranging 0.51–0.55.

Methods

We collected the clinical data and mutational status of 1170 patients with advanced melanoma and established three different predictive models (binary logistic regression, classification and regression trees, and random forest) to forecast the BRAF status.

Conclusions

Up to date statistical models are not able to predict BRAF mutations in an acceptable accuracy. The analysis of the mutational status by sequencing or immunohistochemistry must still be considered as standard of care.

Nodal Basin Recurrence After Sentinel Lymph Node Biopsy for Melanoma: A Retrospective Multicenter Study in 2653 Patients

The objective of this study was to analyze different types of nodal basin recurrence after sentinel lymph node biopsy (SLNB) for melanoma.

PATIENTS AND METHODS

Kaplan-Meier estimates and the Cox proportional hazards model were used to study 2653 patients from 3 German melanoma centers retrospectively.The estimated 5-year negative predictive value of SLNB was 96.4%. The estimated false-negative (FN) rates after 1, 2, 3, 5, and 10 years were 2.5%, 4.6%, 6.4%, 8.7%, and 12.6%, respectively. Independent factors associated with false negativity were older age, fewer SLNs excised, and head or neck location of the primary tumor. Compared with SLN-positive patients, the FNs had a significantly lower survival. In SLN-positive patients undergoing completion lymphadenectomy (CLND), the 5-year nodal basin recurrence rate was 18.3%. The recurrence rates for axilla, groin, and neck were 17.2%, 15.5%, and 44.1%, respectively. Significant factors predicting local relapse after CLND were older age, head, or neck location of the primary tumor, ulceration, deeper penetration of the metastasis into the SLN, tumor-positive CLND, and >2 lymph node metastases. All kinds of nodal relapse were associated with a higher prevalence of in-transit metastases.The FN rate after SLNB steadily increases over the observation period and should, therefore, be estimated by the Kaplan-Meier method. False-negativity is associated with fewer SLNs excised. The beneficial effect of CLND on nodal basin disease control varies considerably across different risk groups. This should be kept in mind about SLN-positive patients when individual decisions on prophylactic CLND are taken.

Lower prevalence of lymphatic metastasis and poorer survival of the sentinel node-negative patients limit the prognostic value of sentinel node biopsy for head or neck melanomas

Head or neck location of primary cutaneous melanomas has been described as an adverse prognostic factor, but this has to be reassessed after the introduction of sentinel lymph node (SLN) excision (SLNE). Descriptive statistics, Kaplan-Meier estimates and Cox proportional hazard models were used to study retrospectively a population of 2302 consecutive melanoma patients from three German melanoma centres undergoing SLNE. Approximately 10% of the patients (N=237) had a primary melanoma located at the head or neck (HNM). In both the SLN-positive and SLN-negative subpopulation, patients with HNM were significantly older, more frequently men and had thicker primaries compared with patients with tumours in other locations. The proportion of positive SLNs was lower in HNM compared with other locations of the primary (20 vs. 26%, P=0.048). The false-negative rate was higher in HNM (17.5 vs. 8.4%, P=0.05). In patients with HNM, the SLN status was a significant factor for recurrence-free survival but not for overall survival. SLN-negative HNM patients had a significantly worse overall survival than the SLN negatives with primaries at other sites, whereas the prognosis of the SLN-positive patients was similar in both groups. The prevalence of lymph node metastases after SLNE is lower in patients with HNM compared with other melanoma locations. As a result, the prognostic information provided by the SLN for HNM seems less important. Decision making for SLNE in HNM should be carefully balanced considering the potential morbidity of the procedure.

Melanomas of the head-and-neck skin with mutation BRAF-V600K or BRAF-V600R define a melanoma subtype with particular clinical features

9098

Background: “Malignant melanoma” is a melting pot of diverse melanocytic tumor entities, which arise in different organs under varying pathogenetic circumstances. Chronic sun exposure is a major factor for the development of cutaneous melanomas of the head-and-neck (HN) region. Methods: 131 patients with metastatic cutaneous melanomas were included in a monocentric retrospective study. The HN skin was the primary tumor site in 41 patients. The mutational hotspots of BRAF and NRAS were analysed by Sanger sequencing. In BRAF and NRAS wildtype cases, additionally exons 11, 13 and 17 of the KIT gene were investigated. HN patients with the mutations BRAF-V600K or BRAF-V600R were defined as group A (n = 11), those with other mutations or wildtype as group B (n = 30). A and B were compared with regard to the emergence of different categories of metastases, using the Kaplan-Meier method and log rank tests. The average follow-up time was 50 months. Results: BRAF-V600K occurred in 10 of the 41 HN patients and in 2 of the 90 non-HN patients (p = 0.003 by T-test), BRAF-V600R in 1 HN and in 1 non-HN patient. KIT mutations were restricted to 2 HN patients. Inversely, NRAS mutations were rare in the HN (3 of 41) versus the non-HN (26 of 90) cohort (p = 0.001). Lymphatic metastasis became apparent in each of the 11 group A patients not later than 35 months after the diagnosis of the respective primary melanoma. 5 out of the 8 group A patients, who underwent sentinel node biopsies (SNB), had nodal micrometastases. During follow-up, regional nodal macrometastases emerged earlier and at a higher rate in group A compared to B (p = 0.044 by log rank test). The same applied even more significantly for satellite/intransit metastases (p = 0.002), whereas for distant metastasis no significant difference was found. Conclusions: BRAF-V600K/R mutations in HN melanomas define a distinct melanoma subtype with an especially high risk of lymphatic metastasis. Clinical implications may be mutation analyses already for primary HN melanomas, and SNB even for thin melanomas of this subtype. Extra-guidelines should be considered for the monitoring of these patients. Special attention to this subgroup is also necessary in clinical trials.

Confocal laser scanning microscopy as a new valuable tool in the diagnosis of onychomycosis - comparison of six diagnostic methods

Onychomycosis is common and can mimic several different nail disorders. Accurate diagnosis is essential to choose the optimum antifungal therapy. The aim of this study was to evaluate the use of confocal laser scanning microscopy (CLSM) and optical coherence tomography (OCT) as new non-invasive diagnostic tools in onychomycosis and to compare them with the established techniques. In a prospective trial, 50 patients with suspected onychomycosis and 10 controls were examined by CLSM and OCT. Parallel KOH preparation, culture, PAS-staining and PCR were performed. PCR showed the highest sensitivity, followed by CLSM, PAS and KOH preparation. OCT offered the second best sensitivity but displayed the lowest specificity. CLSM and KOH preparation showed a high specificity and CLSM offered the best positive predictive value, similar to KOH preparation and OCT. Fungal culture showed the lowest sensitivity and the worst negative predictive value, yet culture and PCR are the only techniques able to identify genus and species. In summary, CLSM was comparable to PAS staining and superior to KOH preparation. Due to the low specificity we assess OCT not as appropriate. In the differentiation of species PCR outplays the fungal culture in terms of time and sensitivity.

Age as a key factor influencing metastasizing patterns and disease-specific survival after sentinel lymph node biopsy for cutaneous melanoma

In our study, we investigated the impact of the constitutional factor age on the clinical courses of melanoma patients with sentinel lymph node (SLN) biopsy. Descriptive statistics, Kaplan-Meier estimates, logistic regression analysis and the Cox proportional hazards model were used to study a population of 2,268 consecutive patients from three German melanoma centers. Younger age was significantly related to less advanced primary tumors. Nevertheless, patients younger than 40 years of age had a twofold risk of being SLN-positive (p < 0.000001). Of the young patients with primary melanomas with a thickness of 0.76 mm to 1.0 mm, 19.7% were SLN-positive. Using multivariate analysis, younger age, increasing Breslow thickness, ulceration and male sex were significantly related to a higher probability of SLN-metastasis. During follow-up, older patients displayed a significantly increased risk of in-transit recurrences (p = 0.000002) and lymph node recurrences (p = 0.0004). With respect to melanoma specific overall survival the patient's age was highly significant in the multivariate analysis. The unfavorable effect of being older was significant in the subgroups with positive and negative SLNs. Age remained also significant for the survival after the onset of distant metastases (p = 0.002). In conclusion, the patient's age is a strong and independent predictor of melanoma-specific survival in patients with localized melanomas, in patients with positive SLNs and after the onset of distant metastases. Younger patients have a better prognosis despite their higher probability of SLN metastasis. Older patients are less frequently SLN-positive but have a higher risk of loco-regional recurrence.

EANM-EORTC general recommendations for sentinel node diagnostics in melanoma

The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, (8) use of dye, (9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.

Interobserver reproducibility of histologic parameters of melanoma deposits in sentinel lymph nodes: implications for management of patients with melanoma

BACKGROUND

: Histologic parameters of melanoma deposits in sentinel lymph nodes (SLNs) have been shown to be predictive of clinical outcome and the presence or absence of tumor in non-SLNs, but assessment of these parameters is prone to interobserver variation.

METHODS

: Histologic sections of 44 SLNs containing metastatic melanoma were examined by 7 pathologists. Parameters assessed included cross-sectional area of tumor deposits, cross-sectional area of SLNs, percentage of SLN area involved by tumor calculated from the 2 previous parameters, estimated percentage of SLN area involved by tumor, tumor penetrative depth, location of tumor within the SLN, and presence of extracapsular spread. Levels of interobserver agreement were measured by using intraclass correlation coefficients (ICC).

RESULTS

: There was good to excellent interobserver agreement on measurement of quantitative parameters: maximal size of largest tumor deposits, calculated area of 3 largest tumor deposits, percentage of the area of SLN involved by tumor, and tumor penetrative depth (ICC, 0.88, 0.73, 0.68, and 0.83, respectively). There was moderate agreement on the evaluation of subcapsular versus nonsubcapsular location of tumor deposits (ICC = 0.50). Agreement on assessment of extracapsular spread was fair (ICC = 0.39).

CONCLUSIONS

: Assessment of some of the quantitative parameters was highly reproducible between pathologists. However, evaluation of the location of tumor deposits within SLNs and assessment of extracapsular spread was less reproducible. Clearer definitions and training can be expected to improve the reproducibility of assessment. These results have important implications for reliability and reproducibility of these parameters in staging, prediction of outcome, and clinical management of melanoma patients. Cancer 2009. (c) 2009 American Cancer Society.

Benefit of sentinel lymphadenectomy for patients with nonulcerated cutaneous melanomas in the Breslow range between 0.76 and 1 mm: A follow-up study of 148 patients

Sentinel lymphadenectomy (SLNE) is now internationally accepted for the primary treatment of melanomas thicker than 1 mm. But it is still controversial whether also patients with nonulcerated melanomas in the Breslow range between 0.76 and 1 mm should be included. At the authors' department, 87 of such patients (Group A) underwent SLNE in combination with wide local excision (WLE) of their primary melanomas in the years 1995 to 2001. SLN micrometastases were found in 10 of these patients (11.5%). Radical completion lymph node dissections (CLND) were added in 4 of the 10 patients without revealing any further nodal metastases. All the 87 Group A patients remained free from recurrent disease at a median follow-up time of 74 months. The control Group B from the same department encompassed 61 consecutive stage Ia patients with melanomas in the identical Breslow range, who had undergone only WLE of their primaries without SLNE in the years 1987 to 1993 (median follow-up time 115 months). Five of these 61 patients (8.2%) developed melanoma metastases within 12 to 68 (median 19) months of follow-up, 3 of them initially in regional lymph nodes. Four of the 5 individuals died because of the final distant dissemination of the melanoma. Kaplan-Meier comparisons between Groups A and B with log-rank testing showed a significantly worse outcome of Group B with respect to recurrence-free survival (p = 0.01), regional nodal progression (p = 0.041), distant metastasis (p = 0.023) and melanoma-related mortality (p = 0.03). The overall survival was not significantly different, because expiries not related to melanoma predominated in both groups. Our data suggest that SLNE seems to nearly completely eliminate the risk of melanoma recurrences in patients with melanomas between 0.76 and 1 mm thick.

Clinical spectrum of cutaneous Langerhans' cell histiocytosis mimicking various diseases

Langerhans' cell histiocytosis summarizes a spectrum of diseases on the basis of histogenetic criteria. These are characterized by an accumulation of cells with Langerhans' cell phenotype in one or multiple organs. Up to 50% of patients with either single or multi-organ manifestation of Langerhans' cell histiocytosis initially present with cutaneous symptoms. Nevertheless, cutaneous Langerhans' cell histiocytosis is rare and heterogeneous in its clinical features and therefore prone to misdiagnosis. We report on five patients, two infants and three adults, suffering from cutaneous Langerhans' cell histiocytosis, either singly or as part of multi-organ disease. The different skin features morphologically mimicking other entities are shown and the differential diagnoses are discussed. The correct diagnosis in all presented cases is based on immunohistological examination, showing a histiocytic infiltrate positively staining with anti-S100 antibodies, CD1a and--apart from one case--with CD207 (langerin).

Pathologic Reporting and Special Diagnostic Techniques for Melanoma

Pathologists play a central role in the management of cutaneous melanoma in determining that a tumor is a melanoma, whether or not it is primary or metastatic, and whether or not the margins of excision are tumor free and in evaluating prognostic indicators from examination of the primary tumor and, where appropriate, lymph nodes, including the sentinel nodes.

Preponderance of the oncogenic V599E and V599K mutations in the B-raf kinase domain is enhanced in melanoma lymph node metastases

Downstream of Ras, the serine/threonine kinase B-raf has been reported to be mutated, amongst other carcinomas, in a substantial subset of primary melanomas, with a preponderance of mutations within the kinase domain, including the activating V599E and V599K transitions. We investigated a representative series of 54 resection specimens of melanoma lymph node metastases for the presence of mutations within the activation segment (exon 15) of the B-raf kinase domain by polymerase chain reaction (PCR) and single-strand conformational polymorphism (SSCP) gel electrophoresis. Sequencing of cloned PCR-SSCP amplicons resulted in 24 (44%) samples harbouring somatic mutations, which is not significantly different from the mutation frequency found in recently investigated primary cutaneous melanomas (Deichmann M, Thome M, Benner A, Näher H. B-raf exon 15 mutations are common in primary melanoma resection specimens but not associated with clinical outcome. Oncology 2004; 66:411-419). The activating mutation T1796A was present in 20 (83%) of these resection specimens, followed in frequency by the oncogenic g1795A mutation in five (21%) cases. With regard to the B-raf protein sequence, the acidic amino acid transitions V599E and V599K were predicted in 15 (62%) and five (21%) of the 24 positive metastases, respectively. The detection of mutations at this hot spot codon was significantly associated with subsequent visceral metastasis (P=0.03; Fisher's exact test). During the transition from primary melanomas (see reference above) to lymph node metastases, the spectrum of B-raf mutations narrows significantly (P=0.00047). The oncogenic B-raf mutations V599E and V599K, as early events in melanocyte transformation, persist throughout metastasis with important prognostic implications.

[Gingival Burkitt lymphoma in a hepatitis C-positive renal transplant patient]

Malignant tumors are a frequent complication in the late phase after organ transplantation. Malignant lymphomas are the second most common tumor, exceeded only by cutaneous carcinomas. Compared to the general population, the organ transplant patients have a 30-60 fold increased risk of developing non-Hodgkin's lymphoma. A 55-year-old, hepatitis C-positive man developed an Epstein-Barr virus (EBV)- negative Burkitt lymphoma (BL) first appearing on the gingiva under immunosuppressive therapy nine years after allogenic renal transplantation. He died 37 days after the onset of polychemotherapy. Immediately before his death, meningeal involvement by the BL was diagnosed. BL after organ transplantation is often found at extranodal sites; it involves the central nervous system more frequently than it does in immunocompetent patients. In 70% of BL occurring after organ transplantation, genes or gene products related to EBV can be demonstrated within the tumor cells. The EBV status of the tumor is of important prognostic significance: EBV-positive BL occurring in organ transplant patients usually responds well to reduction or cessation of immunosuppressive therapy; in some cases permanent complete remissions can be achieved even without chemotherapy. In contrast, patients with EBV-negative BL have a very poor prognosis and hardly respond, even to aggressive chemotherapy protocols.

Sentinel lymphonodectomy and s-classification: a successful strategy for better prediction and improvement of outcome of melanoma

The most successful strategies in the management of melanoma have always been based on early diagnosis and timely surgical removal. Sentinel lymphonodectomy (SLNE) is the most reliable technique for the detection of melanoma micrometastases in regional lymph nodes. The micromorphometric S-classification, a routinely determinable surrogate of tumor burden in the sentinel lymph node (SLN), has high prognostic relevance. SIII metastases, defined by a depth of invasion (d) greater than 1 mm below the capsular level, imply a risk of more than 50% for the presence of nonsentinel lymph node metastases in the same basin and for the emergence of distant metastases within 5 years of follow-up. Corresponding risks with SI metastases (d </= 0.3 mm) and SII metastases (0.3 mm < d </= 1 mm) do not exceed 15%. The survival curve for patients with SIII metastases approaches that of patients in the pre-SLNE era who underwent delayed lymph node dissection for subsequently detected nodal macrometastases. The survival of patients with initially removed SI and SII metastases is much better, similar to that of patients with S0 metastases. This explains the significant survival benefit of SLN-guided surgery in the entire population of patients with melanomas thicker than 0.75 mm, although the outcome of the subgroup without nodal metastases is not influenced by SLNE.

Pathology of the sentinel lymph node in melanoma

The success and further evolution of the sentinel lymph node (SLN) concept decisively depend on histological techniques. Fundamental standards were agreed on by a panel of international experts from various disciplines in 1999 and published as "The Augsburg Consensus" in 2000. Conventional histology (hematoxylin and eosin [H&E]) has to be supplemented by immunohistochemistry (eg, S100 and HMB45) using adequate series of paraffin sections. Melanoma cells in SLNs must be carefully differentiated from capsular and trabecular nevocytes, from immigrated Langerhans cells, from interdigitating dendritic leukocytes, and from nerve sheath cells, which all share S100 positivity in the cytoplasm. The micromorphometric S classification is based on the maximum distance of intranodal melanoma cells from the interior margin of the SLN capsule. It has proven its practicability under routine circumstances, as well as its predictive value regarding further nodal and distant metastases as well as overall survival. This has to be considered in prospective randomized trials dealing with the issues of completion lymphadenectomy and adjuvant therapies of melanoma patients. Reverse-transcriptase polymerase chain reaction (RT-PCR) techniques, when performed as a supplement to histology on the basis of additional paraffin sections, can further enhance the diagnostic sensitivity for detecting melanoma cells in SLNs.

Patients with lymphatic metastasis of cutaneous malignant melanoma benefit from sentinel lymphonodectomy and early excision of their nodal disease

Early versus delayed excision of lymph node metastases is still being assessed in malignant melanoma. In the present retrospective, multicentre study, the outcome of 314 patients with positive sentinel lymphonodectomy (SLNE) was compared with the outcome of 623 patients with delayed lymph node dissection (DLND) of clinically enlarged lymph node metastases. In order to avoid the lead-time bias, survival was generally calculated from the excision of the primary tumour. Survival curves were constructed using the Kaplan-Meier product-limit estimate. Cox's proportional hazards model was used to perform a multivariate analysis of factors related to overall survival. Compared with SLNE and early performed complete lymph node dissection, DLND yielded a significantly higher number of lymph node metastases. Median and mean tumour thickness were nearly identical in the two therapy groups. The estimated 3-year overall survival rate was 80.1+/-2.8% (+/-standard error of the mean (SEM)) in patients with positive SLNs, and 67.6+/-1.9% in patients with DLND (5-year survival rates 62.5+/-5.5 and 50.2+/-5.4%, respectively). The difference between the two survival curves was statistically significant (P=0.002). Using multifactorial analysis, SLNE (P=0.000052), American Joint Committee on Cancer (AJCC) Breslow thickness category (P<0.000001), age (P=0.01) and gender (P=0.028) were independent predictors of overall survival. The location of the primary tumour (P=0.59) was non-significant. Considering only those centres with sufficient data for epidermal ulceration, this risk factor was also significant. In cutaneous malignant melanoma, early excision of lymphatic metastases, directed by the sentinel node procedure, provides a highly significant overall survival benefit.

Sentinel lymphonodectomy in nonmelanoma skin malignancies

BACKGROUND

Whereas the value of sentinel lymphonodectomy (SLNE) in malignant melanoma is established, experience with SLNE in nonmelanoma skin cancers is limited.

OBJECTIVES

The feasibility of SLNE in nonmelanoma skin tumours is evaluated.

METHODS

Thirty-seven patients with high-risk nonmelanoma skin tumours underwent SLNE: 11 squamous cell carcinomas (SCCs), seven Merkel cell carcinomas (MCCs), five cutaneous lymphomas, eight adnexal carcinomas and six other skin cancers, all clinical stage N0.

RESULTS

In nine patients (four MCCs, two SCCs, three lymphomas) the sentinel lymph nodes (SLNs) showed histological evidence of microinvolvement. In five of these nine patients, radical lymph node dissection (RLND) was performed, revealing further micrometastases in three patients (two SCCs, one MCC). No patient with negative SLN showed tumour dissemination during the follow-up over a mean of 2.5 years (range 2 months to 4.5 years, median 2.4 years).

CONCLUSIONS

Our data provide evidence that SLNE is a minimally invasive and highly sensitive staging tool in selected patients with high-risk nonmelanoma skin cancers.

Tyrosinase RT-PCR as a Supplement to Histology for Detecting Melanoma and Nevus Cells in Paraffin Sections of Sentinel Lymph Nodes

The detection of tyrosinase mRNA in sentinel lymph nodes (SLNs) by reverse transcription polymerase chain reaction (RT-PCR) is a sensitive indicator for the presence of melanoma or nevus cells, but it does not enable a distinction between both. We have established an efficient method for extraction and reverse transcription of tyrosinase mRNA from paraffin sections that permits the close correlation of the RT-PCR results with (immuno)histologic findings in adjacent sections. One hundred fifty-three SLNs and 6 non-SLN specimens originating from 92 melanoma and 4 nonmelanoma patients were studied to test the reliability of this approach. The predictive value of positive RT-PCR results was 0.98 for the presence of melanoma or nevus cells; the corresponding negative predictive value was 0.83. Furthermore, the detection rate of tyrosinase mRNA significantly correlated with tumor burden. Among the 33 melanoma-positive SLNs without nevus cells, positive RT-PCR results were obtained in all specimens with extended peripheral (S2) or deeply invasive (S3) micrometastases but in only 46% of the cases with few localized melanoma cells in the subcapsular zone (S1). Routine (immuno)histologic evaluation alone had missed microclusters of melanoma cells in one SLN and small nevus cell aggregates in six other SLNs. They were detected only during microscopic reexamination caused by a positive RT-PCR result. We conclude that histology and immunohistochemistry remain the indispensable gold standard for the identification of melanoma and nevus cells in SLNs. Additional molecular analyses using adjacent paraffin sections may further improve the diagnostic accuracy by sensitizing and guiding the microscopist's attention.

The Augsburg experience: histological aspects and patient outcomes

In Augsburg, sentinel lymphonodectomy (SLNE) was introduced into melanoma treatment in 1994. Diagnostic accuracy has been improved by early identification of sentinel lymph node (SLN) micrometastases and even more by their histomorphometric assessment. The S classification defines three categories of SLN metastases, S1 to S3, supplemented by S0 in the absence of metastasis. It is the leading predictor for the status of the remaining regional lymph nodes and an independent prognosticator for distant metastasis and survival. This should find consideration in adjuvant therapy trials. The pivotal question of whether SLN-guided surgery itself achieves survival benefit has been approached by a follow-up study that compared 387 SLNE-treated patients with 473 patients from the pre-SLNE era. In contrast to nonsignificant differences in patients with thin and very thick primary tumors, death from intermediate-thickness melanoma (1.51 to 4 mm) occurred significantly more often in the watch-and-wait group versus the SLNE group. These results must be validated by prospective randomized trials (e.g., NCI 29605).

Prognostic and therapeutic implications of sentinel lymphonodectomy and S-staging in Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare but very aggressive neuroendocrine neoplasm of the skin with a high propensity for early lymph node metastasis and subsequent distant spread. Optimal treatment and prognostic factors are poorly defined.

OBJECTIVE

The purpose of this study is to assess the prognostic and therapeutic relevance of sentinel lymphonodectomy in MCC.

METHODS

Five patients with biopsy-proven MCC underwent gamma-probe-guided sentinel lymphonodectomy assisted by lymphatic mapping. From each sentinel lymph node (SLN), a series of paraffin sections was histologically and immunohistochemically examined for the presence of micrometastases, which were then staged according to the recently published S classification.

RESULTS

Four of the 5 patients showed metastatic disease in the SLNs, 3 of which were classified as S(2), 1 as S(3). Only 1 of the S(2) patients demonstrated additional positive nodes at completion lymphonodectomy. The patient staged as S(3) refused a radical lymph node dissection and died within 1 year due to widespread metastasis.

CONCLUSIONS

Sentinel lymphonodectomy is a low-morbidity procedure which enables an early detection and exact staging of regional lymph node metastases with potentially high prognostic and therapeutic relevance in MCC.

A micromorphometry-based concept for routine classification of sentinel lymph node metastases and its clinical relevance for patients with melanoma

BACKGROUND

The sentinel lymph nodes (SLNs) as the primary targets for lymphatic metastases can be removed selectively by gamma probe-guided sentinel lymph nodectomy (SLNE) in nearly all patients with cutaneous melanoma. Correspondingly high standards in terms of specificity, sensitivity, and microstaging are required for the evaluation of SLNs.

METHODS

Since 1995, the authors have performed SLNE in 389 lymph node regions (LNRs) on 342 patients with melanoma. The harvested 636 SLNs and a further 1394 nonsentinel lymph nodes (non-SLNs) were evaluated by standardized, semiserial section histology, including immunohistochemistry. For each LNR, this technique permitted routine S classification using two simple morphometric parameters: the number of tumor-involved, 1-mm slices of the SLNs (n) and the centripetal depth of metastatic cell invasion (d). S1 was defined by 1 < or = n < or = 2 and d < or = 1 mm, equivalent to localized peripheral tumor cell deposits; S2 was defined by n > 2 and d < or = 1 mm, indicating more extended peripheral metastases; S3 was defined by d > 1 mm in SNLs with deeper metastatic infiltration; and S0 meant no detectable tumor cells (n = 0).

RESULTS

The authors diagnosed 325 SLNs as S0, 24 SLNs as S1, 22 SLNs as S2, and 18 SLNs as S3. The occurrence of at least one melanoma-positive non-SLN subsequent regional completion lymph node dissection (RCLND) significantly increased from 0 of 12 in S1 SLNs to 2 of 13 in S2 SLNs and 9 of 15 in S3 SLNs (P = 0.001; chi-square test). Like the T classification of the primary melanoma, the S classification proved to be a highly significant predictor for distant metastasis (P < 0.001). It turned out to be an independent factor of influence on distant metastasis and survival in multivariate Cox analyses, which included tumor thickness, primary tumor site, patient gender, and patient age as covariates.

CONCLUSIONS

The data presented recommend the S-staging concept as a promising option to fill a gap between the T and conventional N component of the pTNM classification. If its predictive capacity can be confirmed in multicenter studies, then the S classification may become the decisive criterion for or against RCLND, and a combined T plus S staging system will help to improve prognostically relevant stratification of melanoma patients in adjuvant therapy trials.

[Melanoma. Results with "sentinel node" sampling]

Since June 1995 we have practised a gamma probe guided sentinel lymphadenectomy (SLNE) in 274 patients after injecting a colloidal 99 m-Tc labelled solution around the tumor. By this technique the detection and excision of the SLN succeeded in 99.3% of all cases. We found micrometastases in about 53.1% of patients with pT3 and pT4 melanomas. The specimen of the radical lymph node dissection contained in 30% further metastases. A regional recurrence after SLNE occurred only in one case, a SLN-negative patient.

Secondary lymph node involvement from primary cutaneous large B-cell lymphoma of the leg: sentinel lymph nodectomy as a new strategy for staging circumscribed cutaneous lymphomas

BACKGROUND

Primary cutaneous large B-cell lymphoma of the leg (LBCLL) is a recently defined type of non-Hodgkin's lymphoma. It forms a separate category in the new classification of primary cutaneous lymphomas elaborated by the European Organization for Research and Treatment of Cancer. It is associated with a less favorable prognosis than the most frequently occurring types of primary cutaneous B-cell lymphoma.

METHODS

The authors present four patients with the typical clinicopathologic constellation of LBCLL. Three of them died during the years 1993-1996. The authors reviewed their courses. The fourth patient was staged by sentinel lymph nodectomy (SLNE), i.e., the selective surgical removal and histologic examination of the first draining lymph node associated with the cutaneous tumor.

RESULTS

The courses of the three previous patients were characterized by secondary involvement of regional lymph nodes followed by systemic dissemination of the lymphoma in a third step. Although the conventional staging of the fourth patient had been negative for any extracutaneous lymphoma manifestation, the SLNE revealed initial regional lymph node involvement, which had decisive implications for the choice of therapy.

CONCLUSIONS

SLNE may gain a prominent role in the staging of circumscribed cutaneous lymphomas, in addition to its already established position in melanoma management. Further positive effects of SLNE are 1) better distinction of primary cutaneous lymphomas with secondary lymph node involvement from primary lymph node lymphomas with skin manifestation, and 2) better insight into the biology of different primary cutaneous lymphoma types.

[Erythema necrolyticum migrans after rectal adenocarcinoma]

Necrolytic migratory erythema (NME) is mostly associated with a pancreatic-A-cell-glucagonoma and is considered to be a well-defined cutaneous paraneoplastic syndrome. We report on a 74-year old female who atypically developed a NME after surgical treatment of a rectal adenocarcinoma. Continuous staging and laboratory investigation over four years gave no evidence of any metastasis or further neoplasia.

Characterization of synovial macrophages by monoclonal antibodies in rheumatoid arthritis and osteoarthritis

Inflamed synovium in rheumatoid arthritis (RA) and activated (inflammatory) osteoarthritis (aOA) sometimes demonstrates close similarities in routine histology. If the clinical findings are ambiguous, too, differentiation may become difficult, and the only diagnosis is "chronic unspecific synovitis". By immunohistologic staining with monoclonal antibodies of the Ki-M-series directed against cells of the monocyte/macrophage lineage semiquantitative evaluation of tissue samples is possible thus gaining helpful results for the differential diagnosis. There are significantly more macrophages in RA than in aOA especially in the synovial lining. Proliferating and activation markers also show slight but significant augmentation (OKT9) in RA.