Subungual Melanoma: A Review of Current Treatment

Ultrasound of Nails: Why, How, When

Nail disorders are frequently a challenge to diagnose correctly only based on clinical findings. Moreover, biopsies may leave scars due to damage to the nail matrix. Currently, high-frequency ultrasound (HFUS) with probes >15 MHz is the first-choice imaging technique to study the nail. Compared with other imaging tests such as computed tomography and magnetic resonance imaging, HFUS has the advantage of high-resolution imaging of the nail apparatus without exposure to radiation, contrast media, and the risk of claustrophobia of these other expensive imaging methods. Notably, the axial spatial resolution of HFUS is higher than computed tomography and magnetic resonance imaging; therefore, it can better discriminate the anatomical alterations. Our objective is to review the main applications of HFUS of the nail through literature analysis and illustration of cases of the most frequent pathologies found in our experience, exemplifying why, how, and when HFUS could help diagnose nail diseases.

Reconstruction after Mohs Surgery for Digit Melanoma: Description of Techniques and Postoperative Limb Function

Introduction

Mohs surgery and reconstruction has enabled tissue-preserving resection of cutaneous malignancies. The goal of our case series evaluation is to present reconstructive techniques and functional outcomes in patients undergoing digit-sparing treatment for primary melanoma.

Materials and Methods

A chart review was performed to identify consecutive patients undergoing Mohs surgery and reconstruction for melanoma of the digits. Quality of life (QOL) survey was performed to assess function after the procedure.

Results

Thirty-two patients (13 hand, 19 foot, Age: 65.03 +/-17.78 years) who were undergoing Mohs surgery were identified. No recurrence was identified with an average follow-up of 16.1 months (1-95 months). The average defect size was 5.79 +/-4.54 cm2. Reconstruction was performed 0-4 days after resection. The most common techniques included full-thickness skin graft (FTSG) (N = 7), collagen matrix + FTSG (N = 4), and volar advancement flap (N = 7). The reconstructive technique choice appears correlated with defect size (p = 0.0125). Neuro-QOL upper extremity survey results showed a difference that approached statistical significance between patients who underwent digit-sparing treatment (n = 7) versus direct to amputation controls (n = 5) (p = 0.072). No survey differences between digit-sparing treatment (n = 10) and amputation (n = 8) were identified in the lower extremity (p = 0.61).

Conclusion

Our results show digit-sparing treatment can confirm clear surgical margins and a trend toward improvement in upper extremity function compared with immediate amputation.

Reconstruction of circumferential fingertip defect using free superficial palmar branch of the radial artery flap: Report of two cases

Wide local excision of noninvasive malignant melanomas has been increasingly performed instead of digit amputation, which often results in extensive fingertip defects. Owing to the unique anatomical characteristics of the fingertips, achieving favorable outcomes in both function and cosmesis is challenging during reconstruction. The free superficial palmar branch of the radial artery (SPBRA) flap is advantageous for finger reconstruction. However, its application in circumferential fingertip defects has rarely been reported. In this report, we describe two cases of circumferential fingertip defect reconstruction using a free SPBRA flap after wide local excision of subungual melanoma. The patients were women aged 74 and 63 years at the time of surgery. They presented with subungual melanoma on the right fourth finger and left thumb, in which both biopsies confirmed malignant melanoma in situ (Tis N0 M0), Breslow thickness of 0 mm (noninvasive). After wide local excision, circumferential defects, sized 2.5 × 6 and 2.7 × 7 cm, were formed on their fingertips. A vertically designed free SPBRA flap measuring 2.7 × 6 and 3 × 6 cm was elevated from the unaffected palm in each patient. After performing microvascular anastomosis, the flap was inserted transversely, wrapping the exposed phalangeal bone in a conical shape. The donor site was primarily closed. All flaps survived, and postoperative complications did not develop. Neither local recurrence nor distant metastasis was detected at the latest follow-up in either patient at 24 or 28 months postoperatively. The patients were satisfied with the natural contour of the reconstructed fingertip and recovered functions. In the evaluation of subjective sensory recovery using four scales (excellent, good, fair, and poor), they responded "fair" and "good," respectively. We suggest that the free SPBRA flap could be a reliable reconstructive method for circumferential fingertip defects.

Differences in the Clinical and Molecular Profiles of Subungual Melanoma and Acral Melanoma in Asian Patients

Subungual melanoma (SUM) is a rare type of malignant melanoma that arises beneath the nails. SUM is categorized as a type of acral melanoma (AM), which occurs on the hands and feet. SUM is an aggressive type of cutaneous melanoma that is most common among Asian patients. Recent studies reveal that SUM and AM might have different molecular characteristics. Treatment of melanoma relies on analysis of both clinical and molecular data. Therefore, the clinical and molecular characteristics of SUM need to be established, especially during metastasis. To define the mutation profiles of SUM and compare them with those of AM, we performed next-generation sequencing of primary and metastatic tumors of SUM and AM patients. Subungual location was a better independent prognostic factor than acral location for better overall survival (p = 0.001). Patients with SUM most commonly had the triple wild-type (75%) driven by GNAQ (58%) and KIT (25%) mutations, whereas patients with AM had BRAF (28.6%) and RAF (14.3%) molecular types of mutations. Single-nucleotide variations (SNVs) were more common in SUM than in AM, whereas copy number alterations (CNAs) were more common metastatic lesions of AM. Metastatic tumors in patients with SUM and AM showed increases in CNAs (43% and 80%, respectively), but not in SNVs. The number of CNAs increased during metastasis. When compared with AM, SUM has distinct clinical and molecular characteristics.

Adult and Pediatric Nail Unit Melanoma: Epidemiology, Diagnosis, and Treatment

Nail unit melanoma (NUM) is an uncommon form of melanoma and is often diagnosed at later stages. Approximately two-thirds of NUMs are present clinically as longitudinal melanonychia, but longitudinal melanonychia has a broad differential diagnosis. Clinical examination and dermoscopy are valuable for identifying nail findings concerning malignancy, but a biopsy with histopathology is necessary to confirm a diagnosis of NUM. Surgical treatment options for NUM include en bloc excision, digit amputation, and Mohs micrographic surgery. Newer treatments for advanced NUM include targeted and immune systemic therapies. NUM in pediatric patients is extremely rare and diagnosis is challenging since both qualitative and quantitative parameters have only been studied in adults. There is currently no consensus on management in children; for less concerning melanonychia, some physicians recommend close follow-up. However, some dermatologists argue that the "wait and see" approach can cause delayed diagnosis. This article serves to enhance the familiarity of NUM by highlighting its etiology, clinical presentations, diagnosis, and treatment options in both adults and children.

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.

Current Controversies in Melanoma Treatment

LEARNING OBJECTIVES

After reading this article and viewing the videos, the participant should be able to: 1. Discuss margins for in situ and invasive disease and describe reconstructive options for wide excision defects, including the keystone flap. 2. Describe a digit-sparing alternative for subungual melanoma. 3. Calculate personalized risk estimates for sentinel node biopsy using predictive nomograms. 4. Describe the indications for lymphadenectomy and describe a technique intended to reduce the risk of lymphedema following lymphadenectomy. 5. Offer options for in-transit melanoma management.

SUMMARY

Melanoma management continues to evolve, and plastic surgeons need to stay at the forefront of advances and controversies. Appropriate margins for in situ and invasive disease require consideration of the trials on which they are based. A workhorse reconstruction option for wide excision defects, particularly in extremities, is the keystone flap. There are alternative surgical approaches to subungual tumors besides amputation. It is now possible to personalize a risk estimate for sentinel node positivity beyond what is available for groups of patients with a given stage of disease. Sentinel node biopsy can be made more accurate and less morbid with novel adjuncts. Positive sentinel node biopsies are now rarely managed with completion lymphadenectomy. Should a patient require lymphadenectomy, immediate lymphatic reconstruction may mitigate the lymphedema risk. Finally, there are minimally invasive modalities for effective control of in-transit recurrences.

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.

BRAF V600E Immunohistochemistry Predicts Prognosis of Patients with Cutaneous Melanoma in Thai population

The BRAF V600E mutation in the Thai population has been identified in a considerable percentage of people with cutaneous melanoma. The objectives of this study were to determine the prevalence of this mutation in cutaneous melanomas, conduct a clinicopathological association analysis with the BRAF V600E mutation, and develop a treatment strategy for patients with this mutation that would take advantage of the medications currently available to treat them.

METHODS

Anti-BRAF V600E (clone VE1) immunohistochemistry was performed on 50 pathological samples of cutaneous melanoma after excluding the samples with a low amount of pathologic tissue, a lack of clinical data' and poor follow-up. BRAF V600E expression DNA sequencing was performed to confirm the results of several cases.

RESULTS

Anti-BRAF V600E antibody positivity was noted in 56% (28/50) of cutaneous melanoma cases. DNA sequencing results were consistent with immunohistochemistry results. In cutaneous melanoma, the BRAF V600E mutation was significantly associated with adverse prognosis of patients, including reduced overall survival and disease-free survival.

CONCLUSIONS

An increased prevalence of the BRAF V600E mutation was determined in a collection of cutaneous melanomas in the Thai population, implying that BRAF-targeted therapy may be a promising strategy for patients with BRAF-mutated cutaneous melanoma. This study revealed an association between the clinicopathological aspects of cutaneous melanoma and overall survival, disease-free survival, and overall mortality. A treatment with anti-BRAF-targeted therapy, which incorporates the already available medications' is being researched and developed.

Pigmented Nail Lesions: When to Observe, When to Biopsy, When to Widely Excise, and When to Amputate?

Pigmented nail lesions are challenging problems. The differential diagnosis is broad and ranges from common self-limiting conditions, such as subungual hematoma and infection, to potentially fatal conditions, such as subungual melanoma. Clinical assessment and adjuncts, such as dermoscopy and imaging, are usually insufficient to establish a diagnosis, and a nail bed biopsy is often required. However, this is not an innocuous procedure and may result in permanent nail deformity. In addition, subjecting every patient with nail pigmentation to a biopsy will result in an unacceptably high rate of negative test results. Furthermore, histopathologic diagnosis of subungual melanoma remains challenging for several reasons. Once the diagnosis of subungual melanoma is established, the definitive treatment is controversial because the existing guidelines have largely been adapted from those for cutaneous melanoma. This review presents an approach to the diagnosis and management of pigmented subungual lesions and subungual melanoma, in particular, on the basis of the latest available evidence.

Digital melanoma in Caucasians: a descriptive and survival study according to sublocation

BACKGROUND AND OBJECTIVES

Digital melanoma is an uncommon form of acral melanoma that is anatomically restricted to the finger. The aim of this study is to provide specific epidemiological and clinical information about this subtype of melanoma, as well as to identify differences in recurrence and survival depending on the anatomical sublocation.

PATIENTS AND METHODS

We describe a group of 45 Caucasian patients with digital melanoma divided into three groups: nail unit melanoma (group A), finger skin melanoma (group B), and those melanomas that involve both nail and adjacent skin (group C).

RESULTS

The mean tumor thickness was 4.66 mm, and the most common histological subtype is acral lentiginous melanoma. Group C was more frequent in older men and was thicker and more frequently ulcerated (P < 0.05). In addition, patients in group C developed distant metastases more frequently and had a significantly lower median disease-free survival (26.60 months) compared with group A (69.47 months) and group B (89.81 months) (P < 0.05).

CONCLUSIONS

According to our results, digital melanoma limited to nail apparatus or finger skin was associated with a better prognosis, while those affecting both nail apparatus and skin showed lower melanoma-specific survival.

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.

Functional Surgery for Subungual Melanoma: Surgical Tips Based on Histological Analysis of 21 Cadavers

BACKGROUND

Amputation has been the standard treatment for subungual melanoma. Although there is growing attention toward a more conservative functional surgery, specific operative techniques are not yet available.

OBJECTIVE

We aimed to provide objective measurements for use in functional surgery by analyzing the anatomy of the nail apparatus obtained from 21 cadavers.

MATERIALS AND METHODS

Nailbed thickness was histologically measured in each subunit, and skin surface anatomy was evaluated to determine the proximal resection margin. Immunohistochemical staining was performed to analyze microvessel distribution according to the nail subunit.

RESULTS

The nailbed thickness was the thinnest at the most proximal point of the nail matrix (thumbs, 1.10 ± 0.42 mm; big toes, 1.15 ± 0.37 mm) and the thickest at the hyponychium (thumbs, 2.86 ± 0.82 mm; big toes, 2.72 ± 0.84 mm). The distance from the eponychium to the skin surface closest to the bony cortex of extensor tendon insertion was 6.92 ± 5.13 mm in thumbs and 5.14 ± 1.59 mm in big toes. The median microvessel density was the highest at the hyponychium (25.74 vessels/mm2) and lowest at the germinal matrix (16.26 vessels/mm2) (p < .05).

CONCLUSION

This histological study offers practical tips, including those to help decide the proximal and deep resection margins, in functional surgery.

Near-infrared photoimmunotherapy for the treatment of skin disorders

INTRODUCTION

Near-Infrared Photoimmunotherapy (NIR-PIT) is a novel molecularly targeted phototherapy. This technique is based on a conjugate of a near-infrared photo-inducible molecule (antibody-photon absorber conjugate, APC) and a monoclonal antibody that targets a tumor-specific antigen. To date, this novel approach has been successfully applied to several types of cancer.

AREAS COVERED

The authors discuss the possible use of NIR-PIT for the management of skin diseases, with special attention given to squamous cell carcinomas, advanced melanomas, and primary cutaneous lymphomas.

EXPERT OPINION

NIR-PIT may be an attractive strategy for the treatment of skin disorders. The main advantage of NIR-PIT therapy is its low toxicity to healthy tissues. Cutaneous lymphocyte antigen is a potential molecular target for NIR-PIT for both cutaneous T-cell lymphomas and inflammatory skin disorders.

Salvaging the Digit in Invasive Subungual Malignancies Using a Triple Technique under Awake Local Anesthesia

Introduction

Amputation for subungual malignancy (SUM) was thought to be the gold standard in preventing recurrence and metastasis. The rationale behind this aggressive treatment was never based on scientific evidence. Even though multiple recent studies supported more conservative management by illustrating successful results of the digit salvage technique, especially for "in situ" SUM, this salvage approach is not well supported for the more aggressive type of the "invasive" SUM; herein, we salvaged two cases of "invasive" SUM. Case Presentation. We present two cases of invasive SUM without radiographic evidence of intraosseous involvement, where we avoided digit amputation for both invasive subungual squamous cell carcinoma of the thumb and invasive subungual melanoma of the ring finger. Both were salvaged by using a triple technique under awake local anesthesia which included (I) radical excision of the nail bed unit including both eponychium and periosteum, (II) dorsal cortical bone shaving using a high-speed burr for the distal phalanx, and (III) flap coverage. Brunelli flap was used for the thumb in the first case, and V-Y plasty combined with proximal nail fold advancement flap was used for the ring finger in the second case. There was no evidence of local or distant recurrence, with a good functional outcome after 2.5 years in the first case and 2 years in the second.

Conclusion

Ensuring complete resection with negative margins while preserving the functionality of the affected digit is considered to be the optimal challenge in treating "invasive" subungual malignancies. These two case reports contribute by reporting a successful digit salvage. The safety of this procedure could be confirmed by larger series and longer follow-up periods.

Subungual Melanoma: A Single Institution Experience

Despite the changing paradigms of melanoma treatment in recent years, there remains a relative paucity of data regarding subungual melanoma in the literature. From 2002–2018, 25 patients with subungual melanoma were surgically treated at our facility. A retrospective chart review was conducted to collect relevant demographic, clinical, pathologic, and outcomes data. The median age at diagnosis was 69 years. Most patients (60%) were male, and the melanoma lesion was most often located on the foot (68%). Acral-lentiginous was the most common histologic subtype (59%), and the median Breslow thickness was 3.4 mm. Fifteen patients (63%) underwent a sentinel lymph node biopsy as part of their surgical resection, and four of these patients (27%) had metastatic disease in the lymph nodes. In total, 10 patients underwent lymph node dissection of the involved basin. The median follow up was 21 months in this patient population. Age, gender, tumor location, ulceration, and lesion histology were not significantly associated with recurrence free survival (RFS). Increasing Breslow thickness was found to be significantly associated with shorter RFS (HR: 1.07, CI: 1.03–1.55). In total, 13 patients developed a disease recurrence, and RFS rates were 66% at 1 year and 40% at 3 years. Additionally, 91 and 37% of patients were alive at one year and three years, respectively. Subungual melanomas are rare lesions that often have a more advanced stage at diagnosis, which contributes to the poor prognosis of these cutaneous malignancies.

Melanoma of the Hands and Feet (With Reconstruction)

Melanomas only account for 4% of all dermatologic cancers yet are responsible for 80% of deaths. Notably, melanomas of the hand and foot have a worse prognosis when compared with melanomas of other anatomic regions. Likely this is due to intrinsic biologic characteristics, delayed diagnosis, difficult surgical excision due to delicate anatomy, and lack of definitive diagnostic and therapeutic guidelines. The most common locations of melanoma of the hand, in order of decreasing frequency, are subungual area, dorsal surface, and palmar surface. The most common locations of melanoma of the foot are the plantar surface, dorsal surface, and subungual area, in decreasing frequency. Diagnosis of melanoma of the hand and foot can be difficult because the traditional "ABCDE" (asymmetric shape, border, color, diameter, evolution) rules do not apply. Newer acronyms have been proposed in literature including "CUBED" (colored, uncertain, bleeding, enlarged, delayed) and "ABC rule for Subungual Melanoma." Once diagnosed, treatment is primarily surgical excision and reconstruction. The goal for the surgeon is to maintain the function and anatomy of the hand or foot.

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.

Retrospective analysis of nail biopsies performed using the Medicare Provider Utilization and Payment Database 2012 to 2017

Subungual melanoma (SUM) is subset of acral melanoma that develops within the nail unit and is associated with a poor prognosis. Nail biopsy is the only way to definitively diagnosis SUM. Our objectives were to analyze the Medicare database for nail biopsy utilization and to compare the annual nail biopsy rate with the estimated incidence of SUM in the United States. A retrospective study on nail biopsy data was performed using the Medicare Provider Utilization and Payment Database 2012 to 2017. The number of nail biopsies performed per 100 000 people was compared to SUM incidence per 100 000 people. Podiatrists, dermatologists, other physicians, and NP/PAs respectively performed 12.12, 0.42, 0.08, 0.07 nail biopsies per 100 000 people annually. Dermatologists performed adequate nail biopsies to cover the minimum (0.7%), but not the maximum (3.5%) estimated incidence of SUM. Only 0.28% and 1.01% of general dermatologists and Mohs surgeons, respectively, performed nail biopsies in 19/50 (38.00%) states and 69/929 (7.42%) zip codes. Limitations of our study were that nail biopsies on patients less than 65 years, and those with no or commercial health insurance were not analyzed. In sum, very few dermatologists performed nail biopsies in the Medicare database. Increased efforts are needed to educate dermatologists on nail surgery.

Grafting and Other Reconstructive Options for Nail Deformities: Indications, Techniques, and Outcomes

This article reviews the nomenclature, anatomic components, and physiologic growth involving the perionychium. Fingertip and nailbed injuries are commonly encountered problems in hand surgery. This article focuses primarily on dealing with chronic nailbed deformities following traumatic injury such as nonadherence, split nails, avulsion loss, and hook nails. Nail deformities secondary to pincer nail, mass effect, and pigmented lesions are reviewed as well. The underlying pathology and treatment options are examined for each deformity. The senior author highlights technical pearls and surgical planning for his preferred methods of reconstruction.

Clinical and molecular features of subungual melanomas are site-specific and distinct from acral melanomas

Subungual melanomas (SUM) arise beneath the nails of the hands and feet, and account for 0.7-3.5% of all malignant melanomas. Most studies include SUM in the category of acral melanoma, but understanding the specific features of SUM is critical for improving patient care. In this study, we performed a site-specific comparison of the clinical and molecular features between 54 cases of SUM and 78 cases of nonsubungual acral melanoma. Compared to patients with acral melanoma, patients with SUM were younger at diagnosis, had a higher prevalence of primary melanomas on the hand, and had more frequent reports of previous trauma at the tumor site. SUM was deeper than acral melanoma at diagnosis, which correlated with an increased frequency of metastases. Analysis of common melanoma driver genes revealed KIT and KRAS mutations were predominantly found in SUM, whereas BRAF and NRAS mutations occurred almost exclusively in acral melanoma. We also discovered molecular differences in the cell cycle pathway, where CDK4/CCND1 amplifications were more frequent in SUM and CDKN2A/B loss occurred mostly in acral melanoma, and in the PI3K/mTOR pathway, where RICTOR amplification and TSC1 K587R mutations were exclusively in SUM and PTEN loss and AKT1 mutations were exclusively in acral melanoma. Comparison of hand versus foot tumors revealed more frequent ulceration of SUM foot tumors, which correlated with more distal metastases and poorer overall survival. In summary, we find SUM are both clinically and molecularly distinct from acral melanoma, and our data suggest KIT, CDK4/6, and mTOR inhibitors may be particularly relevant and effective treatments for patients with SUM.

Developing a predictive model for distinguishing invasive nail unit melanoma from nail unit melanoma in situ

BACKGROUND

Clinical information that distinguishes invasive nail unit melanoma from nail unit melanoma in situ before surgery would aid physicians in the decision-making process and estimating prognosis. However, limited information is available on the detailed demographic and dermoscopic features of invasive nail unit melanoma and nail unit melanoma in situ for differential diagnosis.

OBJECTIVE

This study aimed to investigate the demographic data and dermoscopic features of invasive nail unit melanoma and nail unit melanoma in situ and establish a predictive model for differentiating these two forms of nail unit melanoma.

METHODS

A retrospective observational study of ninety-seven patients diagnosed with nail unit melanoma (59 in situ and 38 invasive cases) in four healthcare centres in South Korea (three tertiary referral hospitals and one second referral hospital) from March 2014 to December 2019.

RESULTS

A multivariable analysis revealed that ulcer (odds ratio = 21.6, confidence interval = 2.1-219.8, P = 0.009), total melanonychia (odds ratio = 17.6, confidence interval = 3.0-104.0, P = 0.002), nail plate destruction (odds ratio = 10.9, confidence interval = 2.0-59.4, P = 0.006) and polychromia (odds ratio = 5.3, confidence interval = 1.36-20.57, P = 0.016) were distinctive dermoscopic features of invasive nail unit melanoma. A predictive model with scores ranging from 0 to 6 points demonstrated a reliable diagnostic value (C-statistic = 0.902) in differentiating invasive nail unit melanoma from nail unit melanoma in situ.

CONCLUSIONS

Invasive nail unit melanoma and nail unit melanoma in situ have different dermoscopic features. A predictive model based on morphologic dermoscopic features could aid in differentiating invasive nail unit melanoma from nail unit melanoma in situ.

Art of Prevention: The importance of tackling the nail biting habit

Onychophagia, commonly referred to as nail biting, is a chronic condition that is repetitive and compulsive in nature, and generally seen in children and young adults. Multiple factors play a role in the development of nail biting, ranging from genetic components to underlying psychiatric conditions. Complications of chronic, compulsive nail biting range from obvious distortion of the nail bed unit to ungual and oral infection. Dental hygiene is typically less well-maintained in patients with nail-biting disorders, and teeth may become chipped or notched and gums many become inflamed. Treatment of nail biting involves a multidisciplinary team that provides social, psychiatric, dermatologic, and dental care. Treatment ranges from psychotherapy modalities to medication trials of selective serotonin reuptake inhibitors and N-acetylcysteine. Proper nail hygiene remains a mainstay in the prevention of the complications of chronic nail biting. Additional supportive measures include the support of self-motivational novels and television episodes that help children learn coping mechanisms.

Clinical features of subungual melanoma according to the extent of Hutchinson's nail sign: a retrospective single-centre study

BACKGROUND

Hutchinson's nail sign (HS) is among the diagnostic criteria for subungual melanoma (SUM). However, there is minimal evidence supporting the overall clinical significance of HS in SUM.

OBJECTIVES

To identify clinicopathological features of SUM according to the extent of HS.

METHODS

Retrospective cohort study was performed with consecutive SUM patients at a single centre from January 2006 to December 2017. The extent of HS was defined by the number of affected nail folds (range 0-4). Comparison groups were organized as follows: patients with HS (affecting ≥1 nail folds) vs. without HS; patients with HS affecting ≥2 nail folds vs. HS affecting <2 nail folds; patients with HS affecting ≥3 nail folds vs. HS affecting <3 nail folds. Clinicopathological characteristics of SUM were compared between the groups.

RESULTS

Sixty-one SUM patients were included. Forty-six (75.4%) exhibited HS; 22 (47.8%) on a toe and 24 (52.2%) on a finger. In multivariate analysis, nail destruction [hazard ratio (HR), 10.00; 95% confidence interval (CI), 2.61-38.30; P = 0.001] was significantly associated with the presence of HS and amputation was significantly associated with HS affecting ≥2 nail folds (HR, 4.75; 95% CI, 1.36-16.61; P = 0.015). High T stage (HR, 1.85; 95% CI, 1.20-2.85; P = 0.005, Fig. 2) was significantly associated with HS appearing in ≥3 nail folds.

CONCLUSION

Besides its value of detecting SUM, HS provides useful clinical information. The number of nail folds exhibiting HS could be a useful clinical clue for planning therapeutic strategies for SUM.

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.

Reconstruction for Defects of Total Nail Bed and Germinal Matrix Loss with Acellular Dermal Matrix Coverage and Subsequently Skin Graft

Background and Objectives: Nail bed and germinal matrix loss due to wide excision for fingertip tumors or malignancy are occasionally encountered complications. These defects also result from severely comminuted fingertip crush injuries. Large-area dorsal finger or toenail bed defects, which usually present with phalangeal bone exposure, remain challenging regardless of the usage of different reconstruction strategies. This study aimed to evaluate the clinical outcome of a staged operation with an acellular dermal matrix coverage and subsequent skin graft as reconstruction for defects of total nail bed, germinal matrix loss, and bone exposure. Materials and Methods: From April 2018 to October 2019, four patients with total nail bed, germinal matrix, and bone exposure loss after surgery were enrolled in our series. A staged operation of the acellular dermal matrix coverage with subsequent skin graft was performed on these patients. Skin graft take rate, oncological prognosis, and cosmetic outcome were evaluated. Patients were followed up for 5–13 months. An excellent skin graft take rate with a satisfying aesthetic result without local malignancy recurrence was noted. Minimal functional deficit and donor site morbidity were reported. Results: A staged operation with acellular dermal matrix coverage and subsequent skin graft proves to serve as a feasible strategy for patients who experience total nail bed, germinal matrix loss, and bone exposure after surgery. Conclusions: This reconstruction method provides a reliable repair result, satisfying aesthetic outcomes, as well as having minimal functional deficits and donor site morbidity.

Subungual Tumors: An Algorithmic Approach

The presentation of benign and malignant subungual tumors often follows a final common pathway of nonspecific nail deformity; as such, delays in diagnosis are common. Therefore, it is imperative to have a high degree of suspicion for malignant lesions and an organized approach to subungual tumors. To that end, we present a diagnostic algorithm encompassing the most common benign and malignant subungual tumors, along with a summary of the presentation, imaging, and treatment of these lesions.

Guidelines of care for the management of primary cutaneous melanoma

The incidence of primary cutaneous melanoma continues to increase each year. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is usually curative following early detection of disease. In this American Academy of Dermatology clinical practice guideline, updated treatment recommendations are provided for patients with primary cutaneous melanoma (American Joint Committee on Cancer stages 0-IIC and pathologic stage III by virtue of a positive sentinel lymph node biopsy). Biopsy techniques for a lesion that is clinically suggestive of melanoma are reviewed, as are recommendations for the histopathologic interpretation of cutaneous melanoma. The use of laboratory, molecular, and imaging tests is examined in the initial work-up of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, recommendations for surgical margins and the concepts of staged excision (including Mohs micrographic surgery) and nonsurgical treatments for melanoma in situ, lentigo maligna type (including topical imiquimod and radiation therapy), are updated. The role of sentinel lymph node biopsy as a staging technique for cutaneous melanoma is described, with recommendations for its use in clinical practice. Finally, current data regarding pregnancy and melanoma, genetic testing for familial melanoma, and management of dermatologic toxicities related to novel targeted agents and immunotherapies for patients with advanced disease are summarized.

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.

Missed opportunity to diagnose subungual melanoma: potential pitfalls!

Subungual melanoma, an uncommon form of acral melanoma that arises within the nail matrix, accounts for 1%-3% of all cutaneous melanoma in Caucasians. As subungual melanoma presents in a more disguised manner than cutaneous lesions, increased vigilance is required. It most commonly presents as a discolouration of the nail, nail splitting or nail-bed bleeding. Black pigmentation of the adjacent nail fold, termed Hutchinson's sign, may be a diagnostic clue. Treatment of subungual melanoma remains surgical with wide local excision and amputation primary modalities. We present the case of a 61-year-old man with an 18-month history of a left thumb nail-bed abnormality and a 6-week history of left axillary lymphadenopathy. One year earlier, he presented to the emergency department with a purulent discharge from his left thumb but declined nail-bed ablation. He was referred to the 'Hand and Plastic Injuries Clinic' by his general practitioner and diagnosed with a chronic traumatic-induced nail-bed injury. As his symptoms did not improve, he was referred to the 2-week wait Skin Cancer Clinic. The left thumb nail-bed was excised as a nail unit down to bone, and the diagnosis of melanoma was rendered. Left axillary lymphadenopathy was confirmed as metastatic melanoma. He underwent amputation of his left thumb at the interproximal phalangeal joint, and a left axillary node dissection was performed. No residual melanoma was identified in his thumb. Microscopically, his left axillary dissection confirmed 9 out of 36 positive nodes for metastatic melanoma with extracapsular spread. He was staged at IIIC disease. This case report demonstrates missed opportunities to diagnose subungual melanoma and acts as a cautionary tale in considering this pathology in the differential diagnosis of nail-bed lesions with prompt referral for further investigation.