Pure and Mixed Variants of Desmoplastic Melanoma: A Single-Center, Retrospective, Clinicopathologic Review

BACKGROUND

Desmoplastic melanoma (DM) is a rare melanoma variant. Prognostic indicators and survival vary widely and are further confounded by the histopathologic distinction between pure DM (pDM) and mixed DM (mDM) subtypes. The utility of current treatment guidelines is limited by the lack of evidence-based recommendations.

OBJECTIVE

To compare the clinicopathologic characteristics of pure and mixed subtypes of DMs.

METHODS

All cases of DM were identified from the Washington University in St Louis institutional pathology database between January 2000 and September 2022. Fifty-two cases were identified and subsequently categorized as pure ( n = 26) or mixed ( n = 26). Clinical and histopathologic data were collected and compared.

RESULTS

There were no differences in demographics or tumor location between pure and mixed subtypes. Patients with mDM were more likely to have mitoses present ( p = .03). There were no differences in Breslow depth, tumor diameter, level of invasion, ulceration, and lymphovascular or perineural invasion. The utilization of sentinel lymph node biopsy ( p = .17) and sentinel lymph node positivity ( p = .67) were also similar.

CONCLUSION

Despite histopathologic distinction between pDM and mDM, these subtypes were found to have similar clinicopathologic characteristics, including similar rates of sentinel lymph node metastasis.

Local Recurrence Rates After Excision of Desmoplastic Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Few prospective studies have evaluated local recurrence rates (LRR) after excision of desmoplastic melanoma (DM); however, several retrospective studies have reported high LRR.

OBJECTIVE

To determine LRR after excision of DM and evaluate factors affecting LRR.

MATERIALS AND METHODS

Systematic review of the PubMed, Embase, and Web of Science databases was performed to identify studies reporting local recurrence after excision of DM with conventional wide local excision (WLE), Mohs micrographic surgery (MMS), or staged excision (SE). Meta-analysis was performed to calculate summary LRR and pooled risk ratios (RR).

RESULTS

Literature search identified 4 studies evaluating MMS or SE (total n = 61 DM). 53 studies assessed WLE ( n = 3,080) and were analyzed quantitatively. The overall LRR after WLE of DM was 21% (95% CI, 0.16-0.28; n = 2,308). Local recurrence rate was higher with positive/unknown histologic excision margins (49%, 95% CI, 0.25-0.74; n = 91) versus negative histologic margins (11%, 95% CI, 0.07-0.17; n = 1,075; [ p < .01]). Neurotropism was also associated with increased LRR (RR, 1.79; 95% CI, 1.34-2.38, p < .01; n = 644).

CONCLUSION

DM has high LRR after WLE. Local recurrence risk was greatest with positive excision margins, indicating the importance of achieving negative microscopic margins. Greater study of MMS and SE for DM is required.

Representativeness of initial skin biopsies showing pure desmoplastic melanoma: implications for management

Desmoplastic melanoma (DM) is an uncommon subtype of melanoma with distinct clinicopathological features. It is classified into pure desmoplastic melanoma (PDM) when the proportion of desmoplastic melanoma is ≥90% of the dermally-invasive component, and mixed desmoplastic melanoma (MDM) when the proportion of desmoplastic melanoma is <90%. Studies have reported a lower sentinel lymph node biopsy (SLNB)-positivity rate in PDM compared to MDM and non-DM. As a result, some have recommended not performing SLNB in PDM patients. When PDM is identified in a partial biopsy of a melanoma, there is a risk that sampling bias may under-recognise MDM, but to the best of our knowledge this has not been previously assessed or quantified. The aim of this study was to assess the concordance of the proportion of desmoplastic melanoma in an initial partial biopsy of PDM with the proportion in the entire tumour following complete excision, in patients with cutaneous melanoma. A secondary aim was to determine how frequently this potentially resulted in a patient not receiving a SLNB. Seventy-eight cases of cutaneous melanoma were identified from the Melanoma Institute Australia (MIA) database and 23 cases from the Memorial Sloan Kettering Cancer Centre (MSKCC), where an initial biopsy contained PDM and a subsequent wide excision had residual invasive melanoma. Clinicopathological features were analysed in all patients, including whether a SLNB was performed, the results of SLNB, and any subsequent recurrence. Ninety percent (91/101) of cases were still classified as PDM in the complete wide excision specimen while 10% (10/101) of cases were reclassified as MDM, which was a significant change in classification of final desmoplastic melanoma subtype (p<0.001). The proportion of desmoplastic melanoma was also significantly different between the initial and excisional biopsies (p=0.004). Forty-eight (48/101) patients had a SLNB, of which two (4.5%) were positive for metastatic melanoma; both cases were PDM in the excision specimen. Of the 10 cases demonstrating MDM in the excision specimen, the initial biopsy was a punch biopsy in six cases, shave biopsy in two cases and subcutaneous tissue was sampled in two patients (one punch biopsy, one incisional biopsy). Four of these 10 patients underwent SLNB which was negative in all cases. Twenty-two patients developed recurrence in the follow-up period (median 30 months, range 1-192 months), three with MDM in their excision specimen. One patient did not have a SLNB and developed regional lymph node recurrence. In this study there was a 10% risk that the percentage of desmoplastic melanoma in an initial biopsy of PDM was not representative of the entire lesion, resulting in reclassification as MDM in the excision specimen. If a SLNB is not performed in such cases, a positive SLNB may be missed (one patient in our study) which could impact treatment options for the patient. We recommend caution in not offering a SLNB in the setting of an initial biopsy of PDM if the biopsy is small compared with the overall lesion. If a SLNB is not procured at the time of wide excision in such cases, the SLNs should still be mapped by lymphoscintigraphy to facilitate careful follow up and to enable earlier detection and treatment of nodal disease.

Sentinel lymph node biopsy in desmoplastic melanoma - the percent desmoplastic component matters: A systematic review

BACKGROUND

Desmoplastic melanoma (DM) is a less common form of cutaneous melanoma that has been described for decades; however, controversy remains regarding the management and use of sentinel lymph node biopsy (SLNB). The purpose of this study is to identify whether SLNB is indicated in all cases of DM, including the pure subtype.

METHODS

A systematic review was conducted using PubMed (with access to MEDLINE) along with the Cochrane Central Register of Controlled Trials from 2001 to 2019. Case series and case-control studies were included.

RESULTS

Eighteen studies were included for a total population of 3,914 patients. SLNB was performed in 2229 patients. The percentage of positive SLNB results was 8.5%. However, patients with pure DM (>90% desmoplastic component) were found to have a significantly lower rate of occult metastatic node positivity when compared with that of mixed DM (4.9% and 14.8%, respectively).

CONCLUSIONS

Our findings underscore the importance of the pathologist reporting percentage of desmoplastic component in melanoma. SLNB should be strongly considered for patients with mixed DM. However, the low rate of occult metastatic node positivity in pure DM is beneath the threshold for using SLNB as a staging procedure.

SUMMARY

Previous studies have suggested that desmoplastic melanoma is less likely to metastasize to regional lymph nodes when compared with conventional melanoma. This review suggests that it is imperative to distinguish the histologic subtype of desmoplastic melanoma to determine if staging procedure is indicated.

Surgical Management of Melanoma: Advances and Updates

PURPOSE OF REVIEW

To review and update surgeons about the evolving complexities in the surgical management of melanoma including lymph node staging and treatment.

RECENT FINDINGS

Primary resection with adequate margins continues to be the standard of care for localized cutaneous melanoma. Sentinel lymph node biopsy is confirmed to be a powerful tool due to its prognostic value and informative guidance for adjuvant treatments and surveillance. Due to the lack of benefit in melanoma-specific survival and distant metastasis-free survival, completion lymph node dissection is not performed routinely after a positive sentinel lymph node biopsy. Neoadjuvant systemic treatment approaches for advanced loco-regional disease show promise in phase I and II clinical trial data, and phase III studies. The surgical management of cutaneous melanoma continues to evolve with further de-escalation of the extent of excision of primary melanomas and the management of lymph node disease.

Predictors of Nodal Metastasis in Cutaneous Head and Neck Cancers

PURPOSE OF REVIEW

The complex and varied drainage patterns in the head and neck present a challenge in the regional control of cutaneous neoplasms. Lymph node involvement significantly diminishes survival, often warranting more aggressive treatment. Here, we review the risk factors associated with lymphatic metastasis, in the context of the evolving role of sentinel lymph node biopsy.

RECENT FINDINGS

In cutaneous head and neck melanomas, tumor thickness, age, size, mitosis, ulceration, and specific histology have been associated with lymph node metastasis (LNM). In head and neck cutaneous squamous cell carcinomas, tumor thickness, size, perineural invasion, and immunosuppression are all risk factors for nodal metastasis. The risk factors for lymph node involvement in Merkel cell carcinoma are not yet fully defined, but emerging evidence indicates that tumor thickness and size may be  associated with regional metastasis. The specific factors that predict a greater risk of LNM for cutaneous head and neck cancers generally include depth of invasion, tumor size, mitotic rate, ulceration, immunosuppression, and other histopathological factors.

Systematic review and meta-analysis of local recurrence rates of head and neck cutaneous melanomas after wide local excision, Mohs micrographic surgery, or staged excision

BACKGROUND

Prospective trials have not compared the local recurrence rates of different excision techniques for cutaneous melanomas on the head and neck.

OBJECTIVE

To determine local recurrence rates of cutaneous head and neck melanoma after wide local excision (WLE), Mohs micrographic surgery (MMS), or staged excision.

METHODS

A systematic review of PubMed, EMBASE, and Web of Science identified all English case series, cohort studies, and randomized controlled trials that reported local recurrence rates after surgery for cutaneous head and neck melanoma. A meta-analysis utilizing a random effects model calculated weighted local recurrence rates and confidence intervals (CI) for each surgical technique and for subgroups of MMS and staged excision.

RESULTS

Among 100 manuscripts with 13,998 head and neck cutaneous melanomas, 51.0% (7138) of melanomas were treated by WLE, 34.5% (4826) by MMS, and 14.5% (2034) by staged excision. Local recurrence rates were lowest for MMS (0.61%; 95% CI, 0.1%-1.4%), followed by staged excision (1.8%; 95% CI, 1.0%-2.9%) and WLE (7.8%; 95% CI, 6.4%-9.3%).

LIMITATIONS

Definitions of local recurrence varied. Surgical techniques included varying proportions of invasive melanomas. Studies had heterogeneity.

CONCLUSION

Systematic review and meta-analysis show lower local recurrence rates for cutaneous head and neck melanoma after treatment with MMS or staged excision compared to WLE.

Desmoplastic melanoma: a review of its pathology and clinical behaviour, and of management recommendations in published guidelines

Desmoplastic melanomas are uncommon. Their behaviour differs from that of other melanoma subtypes; therefore, management guidelines for non-desmoplastic melanomas may not be applicable. This review sought to examine all available evidence relating to the behaviour and management of desmoplastic melanomas, based on review of all relevant English-language publications, and to critically assess the recommendations for their management in current published melanoma management guidelines. Compared with other melanoma subtypes, patients with 'pure' desmoplastic melanomas (where ≥90% of the invasive melanoma is of desmoplastic melanoma subtype) have much lower rates of sentinel node positivity and distant metastasis. Local recurrence rates are higher for desmoplastic melanomas, but resection margins wider than those recommended for non-desmoplastic melanomas have not been shown to be of benefit. Adjuvant radiotherapy reduces the risk of local recurrence when a satisfactory histological clearance (≥8 mm) cannot be achieved. Of 29 published melanoma management guidelines identified, only 11 specified management for desmoplastic melanomas, while seven simply stated that the feature should be reported. Desmoplastic melanoma is a unique melanoma subtype with biology that differs from that of other melanoma subtypes. It requires specific management strategies but few current guidelines address these.

Desmoplastic melanoma: an updated clinical review and the emerging role of genetic markers and immunotherapies

Desmoplastic melanoma (DM) is a rare and histopathologically as well as prognostically distinct subset of melanoma that arises in chronically sun-damaged skin. DM is typically and relatively indolent in nature with most cases not progressing to metastatic disease. DM has been managed with both radiation and surgical approaches. Medical options for the treatment of metastatic DM have traditionally been limited. Recent advances in immunotherapies have shown promising responses in DM ushering in a new class of treatment options. Additionally, with the advent of whole exome sequencing, the genetic make-up of DM has been further characterized creating new possibilities for future targeted therapies.

Differing biologic behaviors of desmoplastic melanoma subtypes: Insights based on histopathologic, immunohistochemical, and genetic analyses

Desmoplastic melanoma (DM) is an uncommon variant of melanoma that can be challenging to diagnose. Phenotypic variations in terms of the proportion of spindled cells and fibromucinous stroma have led to the subclassification of pure (>90% spindled cells) and mixed (<90% spindled cells admixed with epithelioid cells) histopathologic DM subtypes. This subclassification is not just semantic; several studies have underscored differences in clinical and prognostic behaviors of the subtypes. In this review, we parse the literature on DM subtypes with an emphasis on histopathologic, immunohistochemical, and genetic data to ascertain whether these factors influence and/or affect their differing biological behaviors. Demographics regarding age, location, and clinical behavior of the subtypes are detailed, as is the impact of dermoscopy as a diagnostic adjunct. Despite the plethora of markers used, our findings suggest that few differentiate between the DM subtypes. Differential expression of PD-L1 suggests that patients with the mixed subtype are likely better candidates for anti-PD/PD-L1 therapy. Significant differences between the subtypes in terms of neurofibromin expression and the frequency of TERT promoter mutations suggest that the subtypes have distinct genetic drivers. Thus, immunohistochemical and genetic analyses imply that these likely affect the biological behaviors of the DM subtypes.

Desmoplastic melanoma: The role of pure and mixed subtype in sentinel lymph node biopsy and survival

Background

Desmoplastic melanoma (DM) is an uncommon type of melanoma. Two histological subtypes of DM can be distinguished: pure and mixed (PDM and MDM). We hypothesized that discrimination between these subtypes is associated with sentinel lymph node biopsy (SLNB) status and survival.

Methods

Clinicopathological data from PALGA, the Dutch Pathology Register were retrieved from patients diagnosed with DM in The Netherlands between 2000 and 2014. Clinical and pathological variables were extracted from pathology text files, including pure or mixed desmoplastic morphology. A Cox proportional hazard model was performed for overall and recurrence‐free survival (OS and RFS).

Results

A total of 239 patients with DM were included, representing 0.4% of all primary cutaneous melanoma in The Netherlands. A total of 114 PDM and 125 MDM patients were identified. MDM was significantly associated with positive SLNB status (P = .035). In multivariable analysis, age (HR 1.10, 95% CI 1.07‐1.14, P < .001) and ulceration (HR 1.98, 95% CI 1.05‐3.75, P = .036) were significant predictors for OS. For RFS, mixed subtype (HR 2.72 95% CI 1.07‐6.89, P = .035), male gender (HR 2.54, 95% CI 1.03‐6.27, P = .043), and Breslow thickness (HR 1.13 per mm, 95% CI 1.05‐1.21, P = .001) were significant predictors.

Conclusion

MDM is significantly associated with a positive SLNB status. Mixed subtype is significantly correlated with RFS, but not with OS. The distinction between pure and mixed desmoplastic subtype therefore seems to be of clinical importance.

Desmoplastic melanoma: Demographic and clinicopathological features and disease-specific prognostic factors

Desmoplastic melanoma (DM) is a rare morphological subtype of melanoma that remains uncharacterized. The aim of the present study was to investigate the incidence of DM, its general demographics, clinicopathological features and disease-specific prognostic factors. DM cases were sampled from the Surveillance, Epidemiology and End Results (SEER) program from between 1973 and 2017. A total of 3,657 cases (median age, 68 years) were identified. The results indicated that DM primarily occurred in Caucasian subjects, with a male-to-female ratio of 2:1. Statistically significant overall survival (OS) and disease-specific survival (DSS) rate differences were identified according to sex, age, treatment, T stage, N stage and SEER historic tumor stage (P<0.05). In multivariate Cox regression analysis, age >68 years, male sex, American Joint Committee on Cancer (AJCC) stage II and III, and SEER historic tumor stage of the regional tumor were all factors associated with poorer OS and DSS rates. The findings also revealed that surgical treatment was associated with favorable DSS and OS rates. In conclusion, DM occurred primarily in Caucasian subjects of 60–80 years of age, with predominance in males. Furthermore, age, sex, AJCC stage, SEER historic tumor stage and surgical treatment were identified as independent prognostic factors of DM in terms of DSS and OS.

Desmoplastic melanoma

Desmoplastic melanoma (DM) is a rare melanoma variant that has unique biology and pathology compared with conventional melanoma (non-DM). Importantly, DM is classified into pure and mixed histologic subtypes, which have been correlated with outcomes. Management of DM broadly mirrors that of non-DM; however, there are unique considerations for DM that influence treatment approaches. This paper will provide a contemporary overview of this disease and will review the literature regarding the management of DM.

Desmoplastic melanoma versus spindle cell melanoma: Incidence and survival, 1973 to 2017

Desmoplastic melanoma (DM) and spindle cell melanoma (SCM) are 2 rare subtypes of melanoma. This study aims to investigate these 2 melanomas comprehensively by comparison.Cases were identified in the Surveillance, Epidemiology, and End Results (SEER) database (1973-2017).A total of 3657 DM and 4761 SCM cases were identified. DM's female-to-male ratio was 1:2 and SCM's was 0.62:1. The age distribution was similar. Both tumor mostly originated from skin and the eye and orbit was SCM-specific tumor site. Comparing both tumors with DM as reference, significant overall survival (OS) were found depending on sex (women, P < .001), age (age ≤65 years, P < .001), race (white, P = .01), tumor orientation (skin, P < .001), T stage (T3 + T4, P = .001), SEER historic stage (regional tumor, P = .04), and surgery (P = .01). Meanwhile, significant disease specific survival (DSS) differences were found depending on sex (men, P < .001), age (age ≤65 years, P < .001), race (white, P < .001), tumor orientation (skin, P < .001), T early stage (T1 + T2, P = .02), T advanced stage (T3 + T4 stage, P = .001), SEER historic stage (regional tumor, P < .001), and surgery (P < .001). The chance of DSS and OS of SCM were significantly higher comparing to DM for female patients (HR = 1.268, for OS; HR = 1.711, for DSS), patients age ≤65 years (HR = 1.290, for OS; HR = 1.638, for DSS), No-Spanish-Hispanic-Latino patients (HR = 1.098, for OS; HR = 1.426, for DSS), patients with skin tumor (HR = 1.174; for OS; HR = 1.444; for DSS) and patients who received surgery (HR = 1.091; for OS; HR = 1.398, for DSS).DM and SCM mostly occurred in white people' skin at 60 to 80 years old and eye and orbit was another most affected site for SCM. SCM had slightly higher occurrence in women and the risk of DSS and OS were significantly higher comparing to DM depending on the women, patients age ≤65 years, patients with skin tumor, No-Spanish-Hispanic-Latino patients and patients who received surgery.

Do you know your guidelines? Diagnosis and management of cutaneous head and neck melanoma

The following article is the next installment of the series "Do You Know Your Guidelines?" presented by the Education Committee of the American Head and Neck Society. Guidelines for the prevention, diagnosis, workup, and management of cutaneous melanoma are reviewed in an evidence-based fashion.

Desmoplastic Melanoma of the Head and Neck: Incidence and Survival, 1992-2013

Objective To describe the epidemiological characteristics and survival of desmoplastic melanoma of the head and neck (DMHN) and discuss the factors influencing survival variation among DMHN, DM of other sites (DMnHN), and conventional melanoma of the head and neck (CMHN). Study Design Retrospective cohort study. Setting Surveillance, Epidemiology, and End Results (SEER) database (years 1992-2013). Subjects and Methods Incidence and survival data for 1095 patients with DMHN, 1139 patients with DMnHN, and 40,257 patients with CMHN were obtained. Kaplan-Meier and Cox proportional hazards regression models were used to calculate survival outcomes. Results Patients with DMHN were diagnosed at greater Breslow thickness ( P < .001), stage ( P < .001), and Clark's level ( P < .001) compared to DMnHN and CMHN. Kaplan-Meier survival analysis demonstrated disease-specific survival (DSS) at 5 and 10 years for DMHN to be 80.5% and 74.7%, respectively, compared with 89.1% and 86%, respectively, for DMnHN and 88.1% and 83%, respectively, for CMHN (log-rank test; P < .001). On multivariate Cox regression analysis, age at diagnosis ( P < .001), Breslow depth >4.00 mm ( P = .006), lymph node status ( P < .001), and presence of ulceration ( P < .001) were found to be independent predictors of DSS for DMHN. Conclusion The increasing incidence and poor survivability of DMHN compared to DMnHN and CMHN are parsimoniously explained by the later stage of disease and depth of invasion at diagnosis, highlighting the importance of improved diagnosis and awareness of DMHN.

Head and neck desmoplastic melanoma: Utility of sentinel node biopsy

PURPOSE

The utility of sentinel lymph node biopsy in desmoplastic melanoma has been questioned due to multiple reports of a low rate of occult nodal metastasis in this variant of melanoma. We describe a single institution experience with management of desmoplastic melanoma of the head and neck and discuss the utility of sentinel lymph node biopsy.

MATERIALS AND METHODS

A retrospective review was performed of 49 patients with desmoplastic melanoma of the head and neck at a tertiary care center from 1994 to 2014.

RESULTS

Sentinel lymph node biopsy was performed in 15 patients. Only 1 (6.7%) of these patients was found to have a positive sentinel node. Of the 46 patients without evidence of neck disease at presentation, 3 (6.5%) were found to have occult nodal disease or developed neck recurrences. When looking at the entire cohort, there were a total of 16 recurrences in 14 patients (28.6%). The majority (85.7%) of recurrences were either local or distant metastasis with only 2 (14.3%) recurrences being in regional lymph node basins. The overall rates of local, regional, and distant recurrences were 14.2%, 4.1%, and 10.2% respectively. The mixed pathologic subtype was not associated with a higher rate of nodal metastasis.

CONCLUSIONS

Desmoplastic melanoma has a low rate of occult nodal metastasis and a high propensity to recur locally or as a distant metastasis, regardless of regional node status. Our experience combined with the uncertain impact that sentinel node status has on survival raises the question of the utility of routine sentinel node biopsy in this specific variant of melanoma.

Desmoplastic melanoma: a challenge for the oncologist

Aim: To evaluate clinical, pathologic and genetic features of desmoplastic melanoma (DM). Materials & methods: Analysis of all DM records from 1991 to 2015. Results: The most common location of DMs was the head and neck (69%); median age and follow-up were 60.5 and 7.3 years, respectively. A familial predisposition for DMs and others malignancies was analyzed. Thin Breslow thickness (<4.5 mm) was associated with an intraepidermal component or a previous lentigo maligna, whereas high Breslow thickness (>4.5 mm) was observed in ‘pure’ DM. Conclusion: DM could progress from an early phase, characterized by an intraepidermal component, to late phase, characterized by a dermal nodule. This hypothesis correlates with melanoma genetic and NF1 mutation, which could be an early event in the progression of DM.

Is sentinel lymph node biopsy warranted for desmoplastic melanoma? A systematic review

BACKGROUND

Desmoplastic melanoma (DM) is an uncommon malignancy associated with a high local recurrence rate. The aim of this systematic review was to determine the positivity rate of sentinel lymph node biopsy (SLNB) in patients with DM. The secondary outcome was to establish if SLNB is warranted for both pure DM (PDM) and mixed DM (MDM).

METHODS

A full systematic literature review of SLNB in DM was performed by two authors in January 2016. Ovid MEDLINE, Ovid EMBASE and the Cochrane Central Register of Controlled Trials were searched.

RESULTS

Sixteen studies involving 1519 patients having SLNB in DM were included, of which 99 patients had positive SLNB (6.5%). Two articles reported a significantly reduced disease-free survival (DFS) with positive SLNB and three published a reduced melanoma-specific survival (MSS). Six studies compared SLNB in MDM and PDM. Of the 275 patients, 38 (13.8%) had a positive SLNB in MDM compared to 17 of 313 patients (5.4%) with positive SLNB in PDM.

CONCLUSIONS

Rates of positive SLNB in DM are reduced compared to other variants of melanoma; however, nodal status may still predict DFS and MSS. MDM is associated with a higher rate of micro-metastases to regional lymph nodes than PDM, and DFS and MSS may be lesser in MDM than in PDM. We would recommend the consideration of SLNB in MDM. However, with such low rates of positive SLNB in PDM, and in the absence of high-risk features to stratify patients, we would not recommend SLNB in PDM.

Clinical utilities and biological characteristics of melanoma sentinel lymph nodes

An estimated 73870 people will be diagnosed with melanoma in the United States in 2015, resulting in 9940 deaths. The majority of patients with cutaneous melanomas are cured with wide local excision. However, current evidence supports the use of sentinel lymph node biopsy (SLNB) given the 15%-20% of patients who harbor regional node metastasis. More importantly, the presence or absence of nodal micrometastases has been found to be the most important prognostic factor in early-stage melanoma, particularly in intermediate thickness melanoma. This review examines the development of SLNB for melanoma as a means to determine a patient’s nodal status, the efficacy of SLNB in patients with melanoma, and the biology of melanoma metastatic to sentinel lymph nodes. Prospective randomized trials have guided the development of practice guidelines for use of SLNB for melanoma and have shown the prognostic value of SLNB. Given the rapidly advancing molecular and surgical technologies, the technical aspects of diagnosis, identification, and management of regional lymph nodes in melanoma continues to evolve and to improve. Additionally, there is ongoing research examining both the role of SLNB for specific clinical scenarios and the ways to identify patients who may benefit from completion lymphadenectomy for a positive SLN. Until further data provides sufficient evidence to alter national consensus-based guidelines, SLNB with completion lymphadenectomy remains the standard of care for clinically node-negative patients found to have a positive SLN.

Surgical Management of Melanoma

The surgical management of melanoma has undergone considerable changes over the past several decades, as new strategies and treatments have become available. Surgeons play a pivotal role in all aspects of melanoma care: diagnostic, curative, and palliative. There is a high potential for cure in patients with early-stage melanoma and the selection of an appropriate operation is very important for this reason. Staging the nodal basin has become widespread since the adoption of sentinel lymph node biopsy (SLNB) for the management of melanoma. This operation provides the best prognostic information that is currently available for patients with melanoma. The surgeon plays a central role in the palliation of symptoms resulting from nodal disease and metastases, as melanoma has a propensity to spread to almost any site in the body.

[Update on surgical treatment of primary and metastatic cutaneous melanoma]

Melanoma is a common cutaneous tumour. It is of great importance due to its increasing incidence and aggressive behaviour, with metastasis to lymph nodes and internal organs. When suspecting melanoma, excisional biopsy should be performed to obtain complete histological information in order to determine the adverse factors such as ulceration, mitosis rate, and Breslow depth, which influence preoperative staging and provide data for sentinel lymph biopsy decision making. The indicated management for melanoma is wide local excision, observing recommended and well-established excision margins, depending on Breslow depth and anatomical location of the tumour. Therapeutic lymphadenectomy is recommended for patients with clinically or radiologically positive lymph nodes. This article reviews surgical treatment of melanoma, adverse histological factors, sentinel lymph node biopsy, and radical lymphadenectomy. Details are presented on special situations in which management of melanoma is different due to the anatomical location (plantar, subungual, lentigo maligna), or pregnancy.

Sentinel lymph node mapping for malignant melanoma of the external auditory canal

We describe a novel technique for sentinel lymph node mapping and biopsy of a primary cutaneous malignant melanoma in the medial portion of the external auditory canal. The approach is illustrated through a case report and technical description of a procedure performed under general anesthesia on a 19-year-old female patient. Due to the hidden and sensitive location of the primary tumor in the medial external auditory canal, the lymphoscintigraphy injection had to be performed by the surgeon immediately prior to the resection of her cT2aN0M0 lesion. Final pathology revealed clear margins at the primary site resection and 2 intraparotid sentinel lymph nodes with microscopic foci of metastatic malignant melanoma, which led to further surgical management. A completion left parotidectomy and neck dissection yielded no additional metastatic disease in the fifty-five nodes that were evaluated. Using this technique, sentinel lymph node mapping and biopsy accurately predicted the highest risk lymph nodes for the primary lesion of the medial portion of the external auditory canal.

Clinicopathologic predictors of survival in patients with desmoplastic melanoma

Background and Objectives

Desmoplastic melanoma is a unique subtype of melanoma which typically affects older patients who often have comorbidities that can adversely affect survival. We sought to identify melanoma-specific factors influencing survival in patients with desmoplastic melanoma.

Methods

Retrospective review from 1993 to 2011 identified 316 patients with primary desmoplastic melanoma. Clinicopathologic characteristics were correlated with nodal status and outcome.

Results

Fifty-five patients (17.4%) had nodal disease: 33 had a positive sentinel lymph node biopsy and 22 developed nodal recurrences (no sentinel lymph node biopsy or false-negative sentinel lymph node biopsy). Nodal disease occurred more often in younger patients and in cases with mixed compared with pure histology (26.7% vs. 14.6%); both of these variables significantly predicted nodal status on multivariable analysis (p<0.05). After a median follow-up of 5.3 years, recurrence developed in 87 patients (27.5%), and 111 deaths occurred. The cause of death was known in 79 cases, with 47 deaths (59.5%) being melanoma-related. On multivariable analysis, Breslow thickness, mitotic rate ≥1/mm² and nodal status significantly predicted melanoma-specific survival (p<0.05).

Conclusions

Nodal status predicts melanoma-specific survival in patients with desmoplastic melanoma. However, since patients with desmoplastic melanoma represent an older population, and a considerable proportion of deaths are not melanoma-related (40.5%), comorbidities should be carefully considered in making staging and treatment decisions in this population.

[Desmoplastic melanoma: a study of 23 cases at 3 centres in the Bouches-du-Rhône region]

BACKGROUND

Desmoplastic melanoma (DM) is a rare form of melanoma, often with atypical and potentially misleading aspects that result in difficult and late diagnosis. Because of the high likelihood of local relapse, practitioners must have a good knowledge of such tumours.

PATIENTS AND METHODS

A retrospective study of the activities of 3 centres in the Bouches-du-Rhône region between 1998 and 2010 enabled us to collate 23 cases of DM and analyse the clinical and histological features of the disease as well as patient survival.

RESULTS

Fifteen of the 23 patients (65.2%) were male with a median age of 64.4 years. Mean Breslow thickness was 7.56 mm. The numbers of AJCC (American Joint Committee for Cancer) stages I, II, III, IV were respectively 4.1, 66.7, 20.8 and 4.1%. Thirteen patients presented relapse, with a mean time to onset of 21 months. The initial relapse involved the skin in 1 case, the lymph nodes in 2 cases, the organs in 5 cases, the organs and subcutaneous region in 1 case, the organs and lymph nodes in 2 cases, and the organs, lymph nodes and skin in 1 case.

DISCUSSION

While DM presents a higher rate of local relapse than classical melanoma, this trend appears to subside in the case of thick DM, in which relapse also involves the lymph nodes and/or organs.

The role of adjuvant radiotherapy in the local management of desmoplastic melanoma

BACKGROUND

In the current study, the authors sought to evaluate outcomes, specifically with respect to adjuvant radiotherapy (RT), for patients with desmoplastic melanoma.

METHODS

The records of 130 consecutive patients who presented between 1985 and 2009 with nonmetastatic desmoplastic melanoma and were treated curatively with either surgery alone (59 patients; 45%) or surgery and postoperative RT (71 patients; 55%) were retrospectively reviewed. Ages ranged from 21 years to 97 years (median age, 66 years). The location of the primary tumor was in the head and neck region in 62% of patients. Only 5 patients (4%) had lymph node involvement at the time of presentation.

RESULTS

The median follow-up was 6.6 years (range, 11 months-24 years). Overall survival rates at 5 years and 10 years were 69% and 53%, respectively. Disease-specific survival rates were 84% and 80%, respectively, at 5 years and 10 years. The actuarial rate of local recurrence was 17% at 5 years and beyond. Of the patients who underwent surgery without receiving postoperative RT, 14 (24%) experienced local recurrence. Of the 71 patients treated with surgery and postoperative RT, 5 (7%) experienced local recurrence. In a Cox multivariate regression model, improved local control was significantly associated with the receipt of postoperative RT (P= .009).

CONCLUSIONS

Surgery followed by postoperative RT appears to provide superior local control compared with surgery alone for patients with desmoplastic melanoma.

A diagnostic algorithm to distinguish desmoplastic from spindle cell melanoma

Spindle cell melanoma and desmoplastic melanoma differ clinically in prognosis and therapeutic implications; however, because of partially overlapping histopathological features, diagnostic distinction of spindle cell from desmoplastic melanoma is not always straightforward. A direct comparison of diagnostic and therapeutic biomarkers has not been performed. Meta-review of the literature discloses key clinicopathological differences between spindle cell and desmoplastic melanoma, including immunophenotypes. Using 50 biomarkers available in routine diagnostics, we examined 38 archival cases (n=16 spindle, 18 desmoplastic, 4 mixed spindle/desmoplastic melanoma). S100 remains as the most reliable routine marker to reach the diagnosis of melanoma in spindle cell and desmoplastic melanoma. We identified nine distinctly labeling markers with spindle cell melanoma showing positivity for laminin, p75, HMB45, c-kit, and MelanA, and desmoplastic melanoma preferentially labeling with collagen IV, trichrome, CD68, and MDM2. On the basis of comparisons of test performance measures, MelanA and trichrome were used to devise a 94% sensitive diagnostic algorithm for the distinction of desmoplastic from spindle cell melanoma. Gene amplification and expression status was assessed for a set of potentially drugable targets (HER2, EGFR, MET, MDM2, TP53, ALK, MYC, FLI-1, and KIT). Fluorescent in situ hybridizations did not reveal a significant number of gene aberrations/rearrangements; however, protein overexpression for at least one of these markers was identified in 35 of 38 cases (92%). In addition, we found BRAF mutations in 31% of spindle cell and 5% of desmoplastic melanoma, with an overall mutation frequency of 16% (n=6/38). We present the first comprehensive screening study of diagnostic and therapeutic biomarkers in spindle cell and desmoplastic melanoma. The devised algorithm allows diagnostic distinction of desmoplastic from spindle cell melanoma when routine histology is not decisive.

Age as a predictor of sentinel node metastasis among patients with localized melanoma: an inverse correlation of melanoma mortality and incidence of sentinel node metastasis among young and old patients

PURPOSE

We have previously reported that older patients with clinical stage I and II primary cutaneous. Melanoma had lower survival rates compared to younger patients. We postulated that the incidence of nodal metastasis would therefore be higher among older melanoma patients.

METHODS

The expanded American Joint Committee on Cancer melanoma staging database contains a cohort of 7,756 melanoma patients who presented without clinical evidence of regional lymph node or distant metastasis and who underwent a sentinel node biopsy procedure as a component of their staging assessment.

RESULTS

Although older patients had primary melanoma features associated with more aggressive biology, we paradoxically observed a significant decrease in the incidence of sentinel node metastasis as patient age increased. Overall, the highest incidence of sentinel node metastasis was 25.8 % in patients under 20 years of age, compared to 15.5 % in patients 80 years and older (p < 0.001). In contrast, 5-year mortality rates for clinical stage II patients ranged from a low of 20 % for those 20-40 years of age up to 38 % for those over 70 years of age. Patient age was an independent predictor of sentinel node metastasis in a multifactorial analysis (p < 0.001).

CONCLUSIONS

Patients with clinical stage I and II melanoma under 20 years of age had a higher incidence of sentinel lymph node metastasis but, paradoxically, a more favorable survival outcome compared to all other age groups. In contrast, patients >70 years had the most aggressive primary melanoma features and a higher mortality rate compared to all other age groups but a lower incidence of sentinel lymph node metastasis.

Malignant melanoma with neural differentiation: an exceptional case report and brief review of the pertinent literature

: The term neurotropic melanoma has been used to refer to malignant melanoma with associated infiltration of nerve or "neural differentiation"--that is, melanoma cells exhibiting cytological characteristics of nerve cells. Historically, neurotropic melanoma has generally been discussed within the context of desmoplastic melanoma. We report an exceptional case of melanoma notable for a very well-differentiated neural component that was contiguous with obvious overlying melanoma. After careful consideration of all pertinent histological features, the overall diagnostic impression was that of melanoma with associated "malignant neurotization." We have not encountered a previously reported case with such a well-differentiated neural component. The following article details our exceptional case of melanoma with "malignant neurotization" and presents a discussion of the differential diagnosis and brief review of the pertinent literature.

Desmoplastic melanoma: a review

Desmoplastic melanoma (DM) is a variant of spindle cell melanoma typically found on chronically sun-damaged skin of older individuals. Early diagnosis can be challenging because it is often amelanotic and has a predominantly dermal component. DM can be difficult to diagnose not only clinically but also histologically, and can be mistaken for a variety of benign and malignant nonmelanocytic spindle cell tumors when viewed on prepared histopathology slides. Pathologists have observed that DMs can manifest significant variation with respect to the extent of intratumoral cellularity, fibrosis, and/or perineural invasion. Furthermore, some tumors present with a pure desmoplastic invasive component (>90%) while other tumors display mixed features of DM and nondesmoplastic melanoma. This has led to the separation of DM into 2 histologic subtypes, pure and mixed. With a focus on the distinction between pure and mixed DM, this review will detail what is currently known about the diagnostic features of DM, discuss risk and prognostic factors, and examine the current literature on disease progression and management.

Desmoplastic melanoma: is there a role for sentinel lymph node biopsy?

BACKGROUND

The utility of sentinel lymph node biopsy (SLNB) for desmoplastic melanoma (DM) is debated. We describe a large single-institution experience with SLNB for DM to determine clinicopathologic factors predictive of SLN metastasis.

METHODS

Retrospective review identified 205 patients with DM who underwent SLNB from 1992 to 2010. Clinicopathologic characteristics were correlated with SLN status and outcome.

RESULTS

Median age was 66 years, and 69 % of patients were male. Median Breslow thickness was 3.7 mm. In 128 cases (62 %), histologic subtype data was available; 61 cases (47.7 %) were mixed and 67 cases (52.3 %) were pure DM. A positive SLN was found in 28 cases (13.7 %); 24.6 % of mixed and 9 % of pure DM had SLN metastases. Multivariable analysis demonstrated that after controlling for age, histologic subtype correlated with SLN status [odds ratio: 3.0 for mixed vs pure, 95 % confidence interval: 1.1-8.7; p < .05]. Completion lymph node dissection was performed in 24 of 28 positive SLN patients with 16.7 % of cases having additional nodal disease. After a median follow-up of 6.3 years, 38 patients developed recurrence and 61 patients died. Positive SLN patients had a significantly higher risk of melanoma-related death compared with negative SLN patients (p = .01).

CONCLUSIONS

The overall risk for SLN metastasis for DM is 13.7 % and is significantly higher for mixed (24.6 %) compared with pure (9.0 %) DM. We believe that these rates are sufficient to justify consideration of SLNB for both histologic variants, especially since detection of SLN disease appears to predict a higher risk for melanoma-related death.