Subungual melanoma: management considerations

Long-term outcomes after amputation and sentinel node biopsy for subungual melanoma: A single-institution series

BACKGROUND

Subungual melanoma (SUM) is a rare tumor with historically poor outcomes. Thus, the benefit of proximal versus distal amputation in SUM remains unclear.

METHODS

We performed a retrospective review of our prospectively-maintained institutional melanoma database, including SUM and non-subungual acral melanoma (AM) patients who underwent sentinel lymph node biopsy (SLNB) between 1999 and 2022. All SUMs had distal joint or proximal amputations. Primary endpoints were overall survival (OS) and recurrence free survival (RFS). Kaplan-Meier estimates, and Cox univariate and multivariate analyses were performed. Tests were repeated on propensity score matched (PSM) populations in a 2:1 ratio.

RESULTS

123 patients underwent resection with SLNB for SUM (n ​= ​27) and AM (n ​= ​96). Median follow-up was 9.2 years. Unadjusted median OS was 149.1 months for AM and 198.1 months for SUM. In the PSM comparison, median OS and RFS remained comparable between SUM and AM (149.5 months versus 198.1 months; p ​= ​0.612). Sentinel node positivity was associated with significantly worse overall survival outcome (Hazard Ratio 5.49; CI (1.59-18.97), p ​= ​0.007). In the PSM population, male sex was also associated with a significant hazard of death (HR 3.00, CI (1.03-8.71), p ​= ​0.043). Proximal amputations were associated with significantly worse OS (p ​< ​0.002) and RFS (p ​< ​0.01) compared to distal amputations in SUM.

CONCLUSION

SUM was well-treated with distal amputations, and had better OS and RFS compared to SUM treated with proximal amputations. Sentinel lymph node status is an important prognostic factor for SUMs and AMs. SUMs can be treated similarly to AMs with comparably good long-term outcomes.

Current surgical management for melanoma

Melanoma is a major malignant cutaneous neoplasm with a high mortality rate. In recent years, the treatment of melanoma has developed dramatically with the invention of new therapeutic agents, including immune checkpoint inhibitors and molecular-targeted agents. These agents are available as adjuvant therapies for postoperative patients with stage IIB, IIC, and III melanomas. Furthermore, neoadjuvant therapy has been studied in several global clinical trials and has demonstrated promising and favorable clinical efficacy, mainly in patients with palpable regional lymph nodes. A recent large phase III clinical trial investigating early lymph node dissection for sentinel lymph node metastases demonstrated no survival benefits. Based on these data, surgery should be reconsidered as an appropriate treatment modality for melanoma. The need for invasive surgical procedures will be reduced with the invention of effective adjuvant and neoadjuvant therapies and novel clinical trial data on regional lymph node dissection. However, surgery still plays an important role in treating early-stage melanoma, accurately determining the disease stage, and effective palliative treatment for advanced melanoma. In this article, we focus on surgery for primary tumors, regional lymph nodes, and metastatic sites in an era of remarkably revolutionary drug treatments for melanoma.

Prevalence of subungual melanoma in patients with cutaneous malignant melanoma: A systematic review and meta-analysis

BACKGROUND

Subungual melanoma (SUM) is a rare type of cutaneous malignant melanoma (CMM) associated with poor prognosis, while data regarding its prevalence are scarce.

OBJECTIVES

We sought to provide a comprehensive systematic review and meta-analysis of the prevalence rates of SUM among all types of CMM, considering certain demographic and clinical characteristics.

METHODS

The MEDLINE electronic database was searched systematically to identify eligible studies providing prevalence rate estimates of SUM in patients with CMM. Included studies were further analysed to estimate the relative prevalences of SUM according to study design, study years, geographical region and sex distribution.

RESULTS

Twenty-eight studies met the inclusion criteria. The overall SUM prevalence was 1.9% (95% CI [1.5%-2.3%]). The prevalence of SUM did not differ significantly between population- and hospital-based studies and remained stable over time. However, it was found to be significantly higher in Asians compared to patients of other geographical regions as well as in studies with more men than women compared to those with female preponderance (p < 0.001).

CONCLUSIONS

In all, the overall SUM prevalence among all subtypes of CMM was estimated at 1.9%, without significant changes over time, and was found to exhibit significant variability between subgroups of different geographical regions.

Foot Melanoma Localized to Subungual Toe Location Portends Poorer Prognosis

Our group previously reported that melanoma of the foot is associated with advanced disease on diagnosis and decreased survival. Lesions localized to the toe appeared to have the worst outcomes. In this study, we both expanded our study to include a 10-year population of patient with invasive melanoma of the foot and ankle and investigated additional factors associated with prognosis. Between January 2007 and December 2016, 211 patients underwent biopsy diagnosis and surgery for invasive melanoma in the BLANK health care system. Demographic, pathologic, staging, and localization characteristics were studied for overall survival. Lesions were localized to dorsal foot, plantar foot, toe (nonsubungual), and toe (subungual) locations. Multivariable analysis found Breslow depth, ulceration, lymph node involvement, and subungual toe location to be associated with poorer survival. Overall survival rate for foot melanoma was 70.6%. Overall survival for nonsubungual toe melanoma was 60.7%, compared to 53.1% for subungual toe melanoma. Of the subungual melanomas, 37.5% of presented as deep lesions with a Breslow depth >4.0 mm. Subungual melanoma was statistically significant for and found to be an independent prognostic factor associated with poorer survival and advanced disease. Based on the results of this study, there should be a low threshold to biopsy suspicious lesions of the toe and foot with particular attention to be dedicated to subungual lesions.

Mohs Micrographic Surgery Is Equivalent to Nail Unit Excision or Amputation for Melanoma In Situ of the Nail Unit: A Systematic Review and Meta-Analysis

BACKGROUND

Local recurrence (LR) rates of melanoma in situ (MIS) of the nail apparatus treated with different surgical modalities are unknown.

OBJECTIVE

To evaluate the differences in LR rates of nail apparatus MIS treated with Mohs micrographic surgery (MMS) versus nail unit excision (NUE) versus amputation.

METHODS

Studies of nail/subungual MIS treated with MMS, NUE, or amputation were identified through multiple literature databases, including PubMed, MEDLINE, Embase, Web of Science, and Cochrane Library. Pooled data were assessed through meta-analyses and Fisher exact test.

RESULTS

Of 280 studies identified, 20 met inclusion criteria (7 comparative studies and 13 single-arm studies). Among the 7 comparative studies, the LR was 4.38% (5/114) after NUE and 2.94% (1/34) after amputation (odds ratio: 0.937; 95% CI: 0.237-3.703). In the 13 noncomparative studies, 23 patients underwent MMS (pooled LR estimate: 11.07%; 95% CI: 3.22%-31.81%) and 140 patients underwent NUE (pooled LR estimate:8.04%, 95% CI: 4.43%-14.16%). The difference in LR rate between MMS, NUE, and amputation was not statistically significant ( p = .578).

CONCLUSION

Local recurrence of nail/subungual MIS in cases treated with MMS was not statistically different than in cases treated with NUE and was comparable to amputation. Further studies investigating the use of MMS for the treatment of nail/subungual MIS are warranted.

A comprehensive analysis of subungual melanomas in a tertiary center: Is amputation outmoded?

Aim: Subungual melanoma is a rare entity. The literature lacks information about its treatment. Alternative treatments exist; amputation or wide local excision (WLE), with or without sentinel lymph node biopsy (SLNB). This study discusses the classical approach for subungual melanoma and compares it with the alternatives. Materials and Methods: A retrospective analysis of subungual melanoma cases between 2008 and 2020 in a tertiary center was done. Results: Thirteen patients were found to have subungual melanoma. Amputation and SLNB were the treatment of choice in 12 patients with invasive diseases. In one patient with a in-situ illness, WLE and SLNB were applied. Mean Breslow thickness was found to be 4.2 mm. The preoperative evaluation showed no signs of metastases in 10 patients, and these patients had SLNB. Two patients had pathological lymph node characteristics in the preoperative evaluation and had elective lymph node dissection (ELND) without SLNB. The mean follow-up was six years, and seven patients died during the follow-ups. Six patients died of natural causes, while one died of systemic disease. Conclusion: Subungual melanoma is a disease that can be controlled with amputation. WLE can be used in in-situ melanomas, but amputation is still a good choice for invasive illnesses.

Nail Apparatus Melanoma: Current Management and Future Perspectives

Nail apparatus melanoma (NAM) is a rare type of cutaneous melanoma that belongs to the acral melanoma subtype. NAM is managed principally in accordance with the general treatment for cutaneous melanoma, but there is scarce evidence in support of this in the literature. Acral melanoma is genetically different from non-acral cutaneous melanoma, while recently accumulated data suggest that NAM also has a different genetic background from acral melanoma. In this review, we focus on recent advances in the management of NAM. Localized NAM should be surgically removed; amputation of the digit and digit-preserving surgery have been reported. Sentinel lymph node biopsy can be considered for invasive NAM for the purpose of accurate staging. However, it is yet to be clarified whether patients with metastatic sentinel lymph nodes can be safely spared completion lymph node dissection. Similar to cutaneous melanoma, immune checkpoint inhibitors and BRAF/MEK inhibitors are used as the first-line treatment for metastatic NAM, but data on the efficacy of these therapies remain scarce. The therapeutic effects of immune checkpoint inhibitors could be lower for NAM than for cutaneous melanoma. This review highlights the urgent need to accumulate data to better define the optimal management of this rare melanoma.

Risk of recurrence of nail unit melanoma after functional surgery versus amputation

BACKGROUND

Minimally invasive nail unit melanoma (NUM) can be treated with functional surgery (FS) instead of amputation.

OBJECTIVE

To determine risk factors associated with recurrence in NUM.

METHODS

We retrospectively reviewed patients with NUM between 2008 and 2022 at a tertiary referral center. Multivariable Cox regression models adjusted for male sex and Breslow thickness (BT) were generated. Receiver operating characteristic analysis was performed to determine optimal cut-off points of the BT for stratifying recurrence risk.

RESULTS

We evaluated 140 NUM cases (33 amputation and 107 FS). The mean BT values were 3.14 ± 2.62 mm (amputation) and 0.70 ± 1.36 mm (FS). Recurrence occurred in 10 (30.30%) patients with amputation and 23 (21.5%) with FS. Distant disease occurred in 10 (30.30%) patients with amputation and 8 (7.48%) with FS. Male sex, greater BT, amelanotic color, ulcers, and nodules were associated with greater risk for recurrence or distant disease. A BT of 0.8 mm was deemed the optimal cut-off for stratifying recurrence risk after surgery (odds ratio, 5.32; 95% CI, 2.04-13.85).

LIMITATIONS

Small sample.

CONCLUSION

FS can be considered for NUM with a BT < 0.8 mm, providing an amputation-sparing benefit. However, NUM with risk factors for recurrence requires patient counselling and close follow-ups.

A Call for Evidence-Based Conservative Management of Nail Unit Malignancies

SUMMARY

Nail unit squamous cell carcinoma and melanoma are the most common malignancies of the nail apparatus. Compared to their cutaneous counterparts, they are diagnosed later and perceived as more aggressive. This may result in overzealous management, including radiographic imaging with poor sensitivity and specificity, interventional nodal staging by sentinel lymph node biopsy, amputation over digit-sparing tumor resections, and elaborate reconstructions after tumor extirpation. In this review article, the authors evaluate the evidence behind several misconceptions in nail malignancy management and provide evidence-based guidance for more conservative care.

Tumor invasion in the hyponychium is associated with distant metastasis and poor prognosis in subungual melanoma: A histologic landscape of 44 cases

BACKGROUND

Subungual melanoma (SUM) has a poor prognosis because of delayed diagnosis. Its progression, consensus on surgical treatment, and correlation with clinical outcomes remain unclear.

OBJECTIVE

We aimed to identify the pattern of dermal invasion in different locations of the nail apparatus and its relationship with prognosis.

METHODS

In this retrospective review of surgically treated SUM patients between January 2011 and April 2019, the nail apparatus was divided into 5 anatomic subunits: the dorsal roof of proximal nail fold, ventral floor of proximal nail fold, germinal matrix, nail bed, and hyponychium. Invasions in the subunits were categorized using 3 criteria: no tumor, in situ tumor, or invasion.

RESULTS

Among 44 cases of SUM, dermal invasion occurred mostly in the distal areas, with 11, 30, 18, 7, and 4 in the hyponychium, nail bed, germinal matrix, ventral floor of proximal nail fold, and dorsal roof of proximal nail fold, respectively. The patients with hyponychial invasion showed a significantly greater Breslow depth (P = .009), a higher rate of lymph node metastasis (P = .019), distant metastasis (P = .036), and shorter disease-free survival (P = .001).

CONCLUSION

Hyponychial invasion is an important prognostic predictor of SUM, given its strong association with invasion depth, metastatic progression, and disease-free survival. Patients with invasion in the hyponychium should undergo more strict workup, treatment, and surveillance.

Melanoma of the Nail Apparatus: An Analysis of Patients' Survival and Associated Factors

BACKGROUND

There are no proper management guidelines for nail apparatus melanoma (NAM).

OBJECTIVE

This study aimed to describe the clinical features, the presence of locoregional and distant metastases and disease-free and overall survival of NAM treated at our institution.

METHODS

A retrospective cohort review of patients with single, primary localized histopathologically confirmed NAM was performed. Collected data consisted of patients' characteristics and tumor features. In addition, local recurrence, locoregional metastases, distant metastases, disease-free survival (DFS) and overall survival (OS) were used as the main outcomes in our analysis.

RESULTS

Thirty patients with NAM were included. The overall survival (OS) in our patients at 5 and 10 years was 85.6 and 73.4%, respectively. DFS was significantly higher in patients with primary tumor location in the hand and without tumor-infiltrating lymphocytes (p value = 0.01 and 0.04, respectively). The patients with in situ melanoma or Breslow thickness <1 mm had a significantly higher chance of DFS and OS (90.0 and 94.1% at 5 years, respectively) than those with thicker NAM (58.3 and 55.6% at 5 years, respectively). A total of 53.3% of 30 patients underwent primary excision and covering with a full-thickness skin graft, while 13.3% of our 30 patients underwent digit amputation. The patients who underwent excision and covering with a full-thickness skin graft showed a complete overall survival (100% at 5 years).

CONCLUSION

Primary tumor location in the hand and lower tumor thickness might be correlated with better patients' survival. The study results suggest that total amputation might not be necessary in all NAM cases.

Management of Nail Unit Melanoma

Nail unit melanoma is an uncommon form of melanoma with worse prognosis compared with nonacral cutaneous melanoma. Nail unit melanoma is often diagnosed at a late stage. Clinical and dermoscopic features may suggest a diagnosis of nail unit melanoma, but confirmation requires histologic analysis. Like the clinical diagnosis, histopathologic diagnosis of nail unit melanoma is also difficult. The surgical management of nail unit melanoma has evolved from aggressive amputations to digit-sparing approaches. This article reviews the clinical presentation, diagnosis, and surgical treatment of nail unit melanoma to promote early diagnosis and rational surgery.

Clinicopathological Features and Prognostic Factors of Primary Acral Melanomas in Caucasians

Background: Cutaneous melanomas located on the acral part of extremities (hand and foot melanoma; HFM) comprise a rare group within all melanomas in Caucasians. HFM is associated with a poor prognosis. We aimed to evaluate clinicopathological features, long-term outcomes, and prognostic factors in primary HFM in Caucasians. Methods: Medical records of all consecutive patients treated between 1997 and 2014 were revised. Patients were diagnosed with primary cutaneous melanoma at I-II clinical stage, and sentinel lymph node biopsy was conducted. The analysis was performed to define the clinicopathological factors influencing outcomes in the HFM and subungual cohort. Among 2537 consecutive patients diagnosed with primary cutaneous melanoma, 247 cases of HFM (9.7%) were found, with a median follow-up time of 7.8 years. Results: Median primary tumor Breslow thickness in subungual melanomas and HFMs was 4.0 mm and 3.3 mm, respectively, significantly higher than in the entire population (median 2.2 mm; p < 0.01). In the HFM group, 37.6% of tumors were ulcerated. Metastases to sentinel lymph node (SLN) were found in 28.3% of HFMs. The 10-year overall survival rate in the HFM group and subungual melanomas was 48.1% and 49.3%, respectively, compared to 63.0% in non-HFM melanomas. Conclusions: Our results confirm that patients with HFMs display worse overall survival compared to the entire melanoma population, with male gender and positive SLN biopsy status acting as independent negative prognostic factors.

Acral Lentiginous Melanoma: Do Surgical Approach and Sentinel Lymph Node Biopsy Matter?

Management of acral lentiginous melanoma (ALM) remains controversial. Traditionally, ALM was managed with digit amputation (DA), resulting in significant morbidity, but recent evidence has advocated for digit sparing management. Furthermore, the significance of nodal metastasis for ALM is not well reported. The aims of this study were to determine if surgical approach for primary ALM impacts outcomes and to evaluate the predictive value of nodal status for ALM.

Japanese Dermatological Association Guidelines: Outlines of guidelines for cutaneous melanoma 2019

With consideration of the ongoing developments in treatment options for cutaneous melanoma, the Japanese Skin Cancer Society published the first guidelines for cutaneous melanoma in 2007 and later revised them in 2015. Here, we report on an English version of the 2019 Japanese Melanoma Guidelines. In this latest edition, all processes were carried out according to the Grading of Recommendations, Assessment, Development and Evaluation system. A comprehensive published work search, systematic review and determination of recommendations in each clinical question were performed by a multidisciplinary expert panel consisting of dermatologists, a plastic and reconstructive surgeon, and a radiation oncologist. The advent of novel agents, such as immune checkpoint inhibitors and molecular-targeted agents, has drastically changed the nature of treatment for adjuvant and advanced-stage diseases among melanoma patients worldwide. Additionally, recent reports of clinical trials regarding surgical procedures and a better understanding of molecular biology and tumor immunology in clinical types of melanoma have had an impact on clinical practise. Based on these viewpoints, eight relevant clinical questions were raised in this report that aim to help clinicians select the appropriate therapeutic approach.

Surgical Management of Lymph Nodes in Melanoma

This article provides a comprehensive evaluation of surgical management of the lymph node basin in melanoma, with historical, anatomic, and evidence-based recommendations for practice.

Confirmatory trial of non-amputative digit preservation surgery for subungual melanoma: Japan Clinical Oncology Group study (JCOG1602, J-NAIL study protocol)

BACKGROUND

Amputation is the standard of care even for early-stage subungual melanomas (SUMs), known as nail apparatus melanoma, because the nail bed and nail matrix are close to the distal phalanx. However, a recent study demonstrated that not all patients with SUMs had histologic invasion of the underlying distal phalanx. As most SUMs occur in the thumb or big toe, amputation of either the thumb or big toe substantially interferes with activities of daily living, including poor cosmesis, loss of function, and phantom pain. Non-amputative digit preservation surgery can thus be applied in such cases without compromising patient prognosis.

METHODS

We are conducting a multi-institutional single-arm trial to confirm the safety and efficacy of non-amputative digit preservation surgery. We will compare our results with those reported in the Japanese Melanoma Study, in which patients underwent amputation for SUMs as a traditional standard of care. Patients aged between 20 and 80 years with stage I, II, or III without evidence of tumor invasion to the underlying distal phalanx on preoperative radiograph are included in the study. The primary endpoint is major relapse-free survival (major RFS), which does not include local recurrence as an event; secondary endpoints include overall survival, digit-preservation survival, relapse-free survival, local relapse-free survival, partial relapse-free survival, and incidence of adverse events. A total of 85 patients from 21 Japanese institutions will be recruited within 5.5 years, and the follow-up period will last at least 5 years. The Japan Clinical Oncology Group Protocol Review Committee approved this study protocol in August 2017, and patient enrollment began in November 2017. Ethical approval was obtained from each institution's Institutional Review Board prior to patient enrollment.

DISCUSSION

This is the first prospective trial to confirm the safety and efficacy of non-amputative digit preservation surgery for SUM without distant metastasis or bony invasion. The results of this trial could provide evidence to support this less-invasive surgery as a new standard of care to preserve adequately functioning digits.

TRIAL REGISTRATION

Registry number: UMIN000029997 . Date of Registration: 16/Nov/2017. Date of First Participant Enrollment: 12/Dec/2017.

Targeted Genomic Profiling of Acral Melanoma

BACKGROUND

Acral melanoma is a rare type of melanoma that affects world populations irrespective of skin color and has worse survival than other cutaneous melanomas. It has relatively few single nucleotide mutations without the UV signature of cutaneous melanomas, but instead has a genetic landscape characterized by structural rearrangements and amplifications. BRAF mutations are less common than in other cutaneous melanomas, and knowledge about alternative therapeutic targets is incomplete.

METHODS

To identify alternative therapeutic targets, we performed targeted deep-sequencing on 122 acral melanomas. We confirmed the loss of the tumor suppressors p16 and NF1 by immunohistochemistry in select cases.

RESULTS

In addition to BRAF (21.3%), NRAS (27.9%), and KIT (11.5%) mutations, we identified a broad array of MAPK pathway activating alterations, including fusions of BRAF (2.5%), NTRK3 (2.5%), ALK (0.8%), and PRKCA (0.8%), which can be targeted by available inhibitors. Inactivation of NF1 occurred in 18 cases (14.8%). Inactivation of the NF1 cooperating factor SPRED1 occurred in eight cases (6.6%) as an alternative mechanism of disrupting the negative regulation of RAS. Amplifications recurrently affected narrow loci containing PAK1 and GAB2 (n = 27, 22.1%), CDK4 (n = 27, 22.1%), CCND1 (n = 24, 19.7%), EP300 (n = 20, 16.4%), YAP1 (n = 15, 12.3%), MDM2 (n = 13, 10.7%), and TERT (n = 13, 10.7%) providing additional and possibly complementary therapeutic targets. Acral melanomas with BRAFV600E mutations harbored fewer genomic amplifications and were more common in patients with European ancestry.

CONCLUSION

Our findings support a new, molecularly based subclassification of acral melanoma with potential therapeutic implications: BRAFV600E mutant acral melanomas with characteristics similar to nonacral melanomas that could benefit from BRAF inhibitor therapy, and non-BRAFV600E mutant acral melanomas. Acral melanomas without BRAFV600E mutations harbor a broad array of therapeutically relevant alterations. Expanded molecular profiling would increase the detection of potentially targetable alterations for this subtype of acral melanoma.

Current management of regional lymph nodes in patients with melanoma

The publication of recent randomized trials has prompted a significant shift in both our understanding and the management of patients with melanoma. Here, the current management of the regional lymph nodes in patients with melanoma is discussed. This review focuses on selection for sentinel lymph node biopsy, management of the positive sentinel node, management of the clinically positive node, and the controversy over the therapeutic value of early nodal intervention.

Nail Apparatus Melanoma: Experience of 10 Years in a Single Institution

Background

Nail apparatus melanoma (NAM) is rare. The higher mortality reported in the literature is most likely due to advanced disease associated with delayed diagnosis and treatment.

Objective

All patients diagnosed with NAM were followed at a single reference center during a period of 10 years, with emphasis on dermatological and histological findings. Clinical outcomes were included.

Methods

A retrospective review of medical records, photographs, and histopathological examination.

Results

73.7% of the patients were female and their mean age was 47 years. Caucasian and African-American patients had a similar incidence (47.4%). There was only 1 Asian patient in this study (5.3%). All patients presented with nail plate pigmentation. The mean prediagnosis duration was 33 months. A total of 63.2% patients had in situ melanoma and an average Breslow index of 2.18 mm in invasive cases. Fifteen patients underwent conservative surgery and 3 underwent phalanx amputation. All patients survived, and 4 have had more than a 5-year follow-up.

Conclusion

In situ lesions showed longitudinal bands or total melanonychia with no nail dystrophy. Invasive cases presented with dystrophic lesions (longitudinal splitting of the nail). Conservative surgery provides a good option without worsening the prognosis. All dermatologists should be aware of early signs of NAM, since prognosis depends on early treatment.

Updated evidence-based clinical practice guidelines for the diagnosis and management of melanoma: definitive excision margins for primary cutaneous melanoma

INTRODUCTION

Definitive management of primary cutaneous melanoma consists of surgical excision of the melanoma with the aim of curing the patient. The melanoma is widely excised together with a safety margin of surrounding skin and subcutaneous tissue, after the diagnosis and Breslow thickness have been established by histological assessment of the initial excision biopsy specimen. Sentinel lymph node biopsy should be discussed for melanomas ≥ 1 mm thickness (≥ 0.8 mm if other high risk features) in which case lymphoscintigraphy must be performed before wider excision of the primary melanoma site. The 2008 evidence-based clinical practice guidelines for the management of melanoma (http://www.cancer.org.au/content/pdf/HealthProfessionals/ClinicalGuidelines/ClinicalPracticeGuidelines-ManagementofMelanoma.pdf) are currently being revised and updated in a staged process by a multidisciplinary working party established by Cancer Council Australia. The guidelines for definitive excision margins for primary melanomas have been revised as part of this process. Main recommendations: The recommendations for definitive wide local excision of primary cutaneous melanoma are: melanoma in situ: 5-10 mm margins invasive melanoma (pT1) ≤ 1.0 mm thick: 1 cm margins invasive melanoma (pT2) 1.01-2.00 mm thick: 1-2 cm margins invasive melanoma (pT3) 2.01-4.00 mm thick: 1-2 cm margins invasive melanoma (pT4) > 4.0 mm thick: 2 cm margins Changes in management as a result of the guideline: Based on currently available evidence, excision margins for invasive melanoma have been left unchanged compared with the 2008 guidelines. However, melanoma in situ should be excised with 5-10 mm margins, with the aim of achieving complete histological clearance. Minimum clearances from all margins should be assessed and stated. Consideration should be given to further excision if necessary; positive or close histological margins are unacceptable.

Improving the diagnosis and treatment of acral melanocytic lesions

Melanocytic lesions of acral sites are common, with an estimated prevalence of 28-36% in the USA. While the majority of these lesions are benign, differentiation from acral melanoma (AM) is often challenging. AM is a unique subtype of melanoma, with distinct molecular characteristics that are thought to contribute to its high rate of locoregional recurrence and worse prognosis. The advent of dermoscopy has since improved the diagnostic accuracy of AM, resulting in earlier detection and arguably improved survival. Additionally, the identification of unique genomic amplifications in AM invites the potential for future AM-specific targeted therapies. Herein, we discuss the importance of dermoscopy in the diagnosis of acral melanocytic lesions and review the treatment strategies for AM.

Assessment of Patient Knowledge of Longitudinal Melanonychia: A Survey Study of Patients in Outpatient Clinics

IMPORTANCE

Subungual melanoma (SM) is a rare subtype of cutaneous melanoma but carries a worse prognosis than similarly staged cutaneous melanomas. Assessing patient knowledge of melanonychia is integral to early diagnosis of SM.

OBJECTIVES

The aim of this paper is to determine patient knowledge of longitudinal melanonychia (LM) and warning signs for SM, frequency of nail self-examinations, and satisfaction of patients with their physician's nail examinations.

DESIGN SETTING AND PARTICIPANTS

We conducted a survey-based study of 363 random patients at Weill Cornell Medicine in New York, USA, performed at 3 different clinics: a general dermatology clinic (n = 167), a nail specialty clinic (n = 44), and a primary care clinic (n = 152).

MAIN OUTCOMES AND MEASURES

Knowledge of the ABCDEF mnemonic for SM was compared to the ABCD mnemonic for cutaneous melanoma. Analyses were performed for patient behavior regarding suspicious nail changes as well as satisfaction with nail counseling and examination.

RESULTS

Only 5% (18/363) of the patients in our study had heard of the ABCDEF mnemonic. In contrast, 9.9% (36/363) of the patients had heard of the ABCD mnemonic for cutaneous melanoma. In total, 37/363 (10.2%) patients reported having LM, 32.4% (12/37) of the patients noted changes in color or width of the band, and 10.8% (4/37) presented with pain or bleeding of the nail, with only 45.9% (17/37) seeking medical attention. Only 11.8% (43/363) of the patients stated that their physician asked them about nail changes, and 1.4% (5/363) of the patients stated that they were counseled about the ABCDEF mnemonic. In comparison, 13.8% (50/363) of the patients were advised on the ABCD mnemonic for the cutaneous melanoma mnemonic. While 70.2% (255/363) of the patients stated that they used sunscreen or wore sun-protective clothing, only 31.4% (114/363) assessed their nails for color changes, with 54.9% (128/233) of the patients categorizing themselves as "very unsatisfied" with the evaluation of their nails by their dermatologist.

CONCLUSIONS AND RELEVANCE

Our data shows that there is a lack of patient knowledge of LM and warning signs for SM. Further testing is needed to determine whether educating patients about LM, warning signs for SM, and nail self-examinations would improve patient outcomes.

Malignant Melanoma of the Nail Apparatus

Background. Malignant melanoma of the nail apparatus is exceedingly rare. Increasingly, genetic studies have been employed to aid in distinguishing between malignant melanoma and benign melanocytic nevi. Methods. Archived nail apparatus melanomas were analyzed by fluorescence in situ hybridization (FISH) using probes targeting the genes at 6p25 (RREB1), 11q13 (CCND1), 8q24.1 (MYC), 6q23 (MYB), 9p21 (CDKN2A) and the centromeres of chromosomes 8 (D8Z2) and 6 (D6Z1). The results were correlated with clinical and demographic information. Results. Mean patient age was 57.8 years (range 23-92 years). In all, 5 of 7 (71%) cases involved the upper extremity digits. RREB1 gain was seen in all cases. CCND1 gain was seen in 6 of 7 (86%) cases, 3 of which were amplified. MYB loss and MYC gain were both seen in 5 of 7 (71%) cases. Homozygous loss of CDKN2A was not observed in any case. Two of 7 (28.6%) patients had lymph node metastasis and died of widely metastatic disease. These 2 patients harbored the most genetic aberrations: gains of RREB1, CCND1, and MYC, and MYB loss. Both benign melanocytic nevi controls showed normal FISH results. Conclusions. RREB1 and CCND1 gains are common in nail apparatus melanoma as in most melanomas, and an increased number of genetic aberrations may be associated with a poorer prognosis, though the limited number of cases precludes definitive correlation. FISH appears to be a useful adjunct in the diagnosis of nail apparatus melanomas and improves diagnostic confidence even in the setting of unambiguous histomorphology.

Dermatologic Manifestations of the Lower Extremity: Nail Surgery

Nail surgery is a fundamental component of podiatric surgery. Nail disorders are common and may cause significant morbidity and occasionally mortality. Diagnosis of inflammatory and infectious conditions, and of benign or malignant tumors, often requires a biopsy of the nail unit. Excisional surgery may also be curative for certain tumors. This article reviews key elements of nail anatomy, surgical preparation, local anesthesia, and methods to achieve and maintain a bloodless field. A familiarity with these concepts should allow clinicians to develop a surgical plan and approach when patients present with a nail disorder requiring biopsy or surgical treatment.

Tumor-to-bone distance of invasive subungual melanoma: an analysis of 30 cases

Subungual melanoma (SUM) is rare and represents approximately 2-3% and 20% of all cutaneous melanomas in Caucasians and Asians, respectively. Amputation has usually been performed for invasive SUM; however, not all invasive SUMs invade or attach to the distal phalanx. To investigate the possibility of non-amputative surgery for patients with invasive SUM, the distances between the deepest base of the melanoma cells and the bony surface in the surgical specimens of invasive SUM were measured. Thirty surgical specimens of invasive SUM were retrospectively reviewed. The contents of the specimens were as follows: 14 first toes, 10 thumbs, three second fingers, two third fingers, and one fifth finger. Four specimens showed bone invasion, and the tumor was attached to the bone in four specimens. The tumor-to-bone distance exceeded 0.9 mm in all the specimens with thicknesses <4 mm. In the non-ulcerated SUMs (nine specimens), only one SUM specimen showed bone attachment. There was a higher likelihood of bone attachment or invasion when tumor thickness (TT) exceeded 4 mm (Pearson chi-square test, P = 0.009; Fisher exact test, P = 0.004; student t test, 0.033). Univariate and multivariate analysis also revealed that thick TT had a statistically significant affect (odds ratio 1.807 and 1.865, 95% CI 1.11-3.01 and 1.11-3.13, P = 0.023 and 0.018). Non-amputative surgery may be possible for SUM tumors that are of intermediate-thickness. However, there has been little evidence demonstrating survival with non-amputative surgery for invasive SUM. A large, randomized, prospective clinical study is required to address this issue.