Nail Unit Melanoma Research Articles

Ultrasonographic evaluation of nail matrix topography for preservative nail surgery of nail unit melanoma.

Recently, functional or preservative surgery has been preferred for nail unit melanoma; however, complete resection of the nail unit, particularly the matrix, is challenging because of its complex structure. This study aims to measure the distance of important nail structures through ultrasonography. Herein, 14 patients without nail deformity were included. The length from the nail cuticle to the distal interphalangeal joint (distance X), to the attachment part of the extensor muscle (distance A), to the median proximal end of the nail matrix (distance B), and to the lateral proximal end of the nail matrix (distance C) were measured. In the axial plane, the length from the highest point of the nail plate to the bottom of the distal phalanx (distance Y) and to the lateral tip of the nail plate (distance D) were measured. On the first fingernail, third fingernail, first toenail, and third toenail, the mean ratio A:X, ratio B:X, ratio C:X, and ratio D:Y were 78.6%, 44.3%, 57.2%, 40.1%, and 84.6%; 55.9%, 64.9%, 40.2%, and 66.4%; 35.6%, 50.8%, 34.3%, and 81.9%; and 57.2%, 59.6%, and 31.7%, respectively. Nail units are often invisible to the naked eye; thus, this study will help identify the approximate scope of excision.

Looking Beyond the Hutchinson Sign: A Retrospective Study of Clinical Factors Indicating the Presence and Invasiveness of Nail Unit Melanoma in Patients With Longitudinal Melanonychia.

The data underlying this article are available in the article.Longitudinal melanonychia (LM) presents a challenge because nail unit melanoma (NUM) must be considered as a differential diagnosis. Because nail matrix biopsy may result in nail dystrophy, it is important to distinguish NUM from LM. To provide evidence of previously reported clinical factors indicative of NUM in patients with LM. This was a retrospective study of patients who presented with LM and had biopsy-confirmed NUM from 2005 to 2021. Benign LM was either confirmed by biopsy or considered benign if followed without the need for biopsy. Clinical factors associated with LM and NUM were compared by multivariate regression. A total of 177 patients (97 LM and 80 NUM) were included. Multivariate regression showed that high band color intensity (p = .0031), variegation (p = .0005), nail plate splitting (p = .0017), Hutchinson sign (p = .0027), and band change (p = .001) correlated with malignancy. Nail plate splitting was associated with Breslow thickness. Malignancy should be suspected and biopsy performed in patients with LM and high band color intensity, variegation, nail plate splitting, Hutchinson sign, and band change.

Clinical and dermoscopic features of nail unit melanoma in an Australian nail clinic cohort.

Nail unit melanoma carries diagnostic challenges conferring with its poor prognosis. This audit aims to characterise both clinical and dermoscopic features of nail unit malignant lesions and compare them with biopsied benign lesions. It focuses on informing future practice by aiding in the stratification and recognition of malignant diagnostic patterns in the Australian context.

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.

Clinicohistopathologic challenges and traps in the diagnosis of nail unit melanoma.

Melanoma of the nail apparatus is challenging to diagnose for both dermatologists and dermatopathologists. Misdiagnosis or delayed diagnosis of nail unit melanoma can have fatal consequences and legal ramifications. This review educates dermatopathologists on challenges and traps they should be aware of to avoid misdiagnosis of nail unit melanoma. We present illustrative difficult cases that introduce several themes regarding challenges in the diagnosis of nail unit melanoma: specimens with subtle histopathologic findings, challenges in immunoperoxidase interpretation, and how clinical knowledge and surgical procedural knowledge are mandatory to make the diagnosis. Dermatopathologists will be aware of when and how to suspect nail unit melanoma in unusual circumstances.

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

Minimally invasive nail unit melanoma (NUM) can be treated with functional surgery (FS) instead of amputation. To determine risk factors associated with recurrence in NUM. 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. We evaluated 140 NUM cases (33 amputation and 107 FS). The mean BT values were 3.14±2.62mm (amputation) and 0.70±1.36mm (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 0.8mm was deemed the optimal cut-off for stratifying recurrence risk after surgery (odds ratio, 5.32; 95% CI, 2.04-13.85). Small sample. FS can be considered for NUM with a BT<0.8mm, providing an amputation-sparing benefit. However, NUM with risk factors for recurrence requires patient counselling and close follow-ups.

A call for nail clipping histopathology to become an essential component of the routine evaluation of melanonychia: Benefitting patients as a triage and surgical planning maneuver.

We call on dermatologists and dermatopathologists to include nail clipping histopathology as an essential component of the routine evaluation of melanonychia. This manuscript demonstrates a case where an adult woman with broad melanonychia of the right thumbnail declined a nail matrix biopsy, but was amenable to a nail clipping.The nail clipping showed pigmentation, melanocyte remnants, and small cavities in the nail plate. These features have been published previously by our group as a clue to nail unit melanoma within nail clippings.This patient was rapidly triaged for nail matrix biopsy, which demonstrated nail unit melanoma in situ. Every patient with melanonychia can benefit from a nail clipping by examination of the location of the pigmentation within the nail plate for surgical planning, and if melanocyte remnants are detected, the nail clipping also serves as a rapid triage mechanism for nail matrix biopsy to evaluate for nail unit melanoma. Fontana-stained sections will highlight the pigmentation in the nail plate, and its location in the nail plate can easily be described by the dermatopathologist. Nail clippings performed in the setting of clinically apparent melanonychia may show helpful histopathologic findings of pigmented fungi, hemorrhage, external pigmentation, features of other pigmented nail unit tumors, as well as other entities. Nail clipping histopathology can provide extensive information in the evaluation of melanonychia with minimal discomfort for a patient, and little disruption to a physician's clinic flow. With this additional case of a nail unit melanoma diagnosed after initial concern found in a nail clipping, as well as other information in the literature, it is clear that melanocyte remnants found in nail clippings are reliable concerning features related to nail unit melanoma in adults. With knowledge of these histopathologic features in nail clippings and the significance of melanocyte remnants, the dermatopathologist can play a crucial role in the use of a nail clipping as a life-saving diagnostic maneuver. Accordingly, given the potential benefit to patients in this setting, as well as other uses of a nail clipping in the evaluation of melanonychia, we call on dermatologists and dermatopathologists to innovate the routine evaluation of melanonychia through the routine employment of nail clippings for histopathologic evaluation.

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

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. 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). 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). 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.

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

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. 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. 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. 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. 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.

Commentary on Nail Unit Melanoma In Situ Treated With Mohs Micrographic Surgery.

Commentary on Nail Unit Melanoma In Situ Treated With Mohs Micrographic Surgery.

Commentary on Mohs Micrographic Surgery Using MART-1 Immunostaining for Nail Unit Melanoma in Situ.

Commentary on Mohs Micrographic Surgery Using MART-1 Immunostaining for Nail Unit Melanoma in Situ.

Nail Unit Melanoma In Situ Treated With Mohs Micrographic Surgery.

Mohs micrographic surgery (MMS) is under used in the treatment of nail unit melanoma in situ (MIS), with limited studies in the literature. Report clinical outcomes for nail unit MIS using MMS with melanoma antigen recognized by T cells-1 (MART-1) immunostaining. A retrospective observational study at a single academic institution of patients with a diagnosis of nail unit MIS treated with MMS with MART-1 immunostaining from January 1, 2006, to December 30, 2016. The primary outcome measure was the recurrence rate after MMS. Fourteen patients were identified. With an average follow-up of 6.0 years (71.6 months; range = 5-139 months), 1 patient developed recurrence 6.6 years after undergoing initial MMS, requiring amputation with no further treatment or recurrence thereafter. Mohs micrographic surgery for nail unit MIS offers a high cure rate similar to other surgical modalities and can reduce the need for digital amputation. The evolution of the Mohs technique over time, namely, using MART-1 immunostaining, has led to improvement in treatment outcomes. Performing complete nail unit excision with nail plate remaining intact attached to the nail bed may also contribute to improved outcomes. Further refinement in technique and more data are necessary to continue to advance this treatment.

Clinicopathological significance of tumor-infiltrating lymphocytes and programmed death-1 expression in cutaneous melanoma: a comparative study on clinical subtypes

Interactions between immune cells and tumor cells play an important role in tumor progression. We evaluated patterns of tumor-infiltrating lymphocytes (TILs) and programmed death-1 (PD-1) expression in acral and nonacral cutaneous melanoma, and determined their effects on clinicopathological characteristics and biologic responses. We identified 122 cases of cutaneous melanoma, of which 39 were cases of non-nail unit acral melanoma (NNUAM), 35 were cases of nail unit melanoma (NUM), and 48 were cases of nonacral melanoma. Clinicopathological features and survival outcomes were analyzed according to the scores for TILs and PD-1 expression in intratumoral and peritumoral compartments. The effects of the presence of TILs and PD-1 expression on various clinicopathological factors differed according to the clinical subtypes of cutaneous melanoma. The frequency of intratumoral TILs and PD-1 expression were lower in NUM than in the other two subtypes. The density of peritumoral PD-1 was significantly higher in NNUAM. In NUM and nonacral melanoma, a low density of intratumoral TILs and PD-1 was associated with a deeper Breslow thickness and the presence of a vertical growth phase. In NNUAM, a high density of peritumoral TILs and PD-1 was associated with a shallower Breslow thickness and less frequent extracutaneous dissemination. In NNUAM, a high density of peritumoral PD-1 was associated with a better prognosis. This study suggests that the effects of PD-1+ TILs on biological activity differ according to the clinical subtypes of cutaneous melanoma.

In situ nail unit melanoma: epidemiological and clinic-pathologic features with conservative treatment and long-term follow-up.

Nail unit melanoma (NUM) is a rare melanoma variant, usually associated with a poor prognosis because of a delayed diagnosis. Few data are available concerning the management and long-term outcome of in situ NUM. To use a large cohort to provide comprehensive patient data and long-term follow-up information. This will serve to investigate distinctive epidemiological, clinical and histological features of in situ NUM. To report treatment modalities, assess conservative surgery and evaluate its long-term safety. Patients with confirmed diagnosis of in situ NUM were retrospectively reviewed. Demographics, clinical presentation, therapeutic data and follow-up were analysed. Sixty-three cases of in situ NUM were identified as follows: 44 were women (70%), with a mean age of 51 years. The mean duration of symptoms prior to consultation was 4.3 years [range 3 months-28 years]. Clinically, with 58 cases, i.e. (92%) longitudinal melanonychia was the most common clinical presentation. The thumb was the most affected digit, being afflicted in 28 cases: 44%. Medical history found a widening and/or recent darkening of the melanonychia in 46 cases (82%). The treatment consisted of, respectively, 56 En bloc excisions of the nail apparatus 89% of the patients we studied, and seven amputations of the distal phalanx. During the follow-up period (mean: 10 years), two patients presented in situ recurrences. The recognition of a NUM at an in situ stage allows early treatment and curing of this tumour. At this early stage, a 'functional surgery' is a rational approach with an excellent oncologic safety.

Two-phase Surgery Using a Dermal Regeneration Material for Nail Unit Melanoma: Three Case Reports

Background:Nail unit melanoma (NUM) poses a considerable treatment challenge, particularly in cases with in situ or early invasive lesions, and wide excision with phalanx amputation. For post-excisional skin defects, stump plasty and/or split-thickness skin grafting may cause persisted irritation and ulceration as a post-operative complication, because of the insufficient underlying tissue volume, vascularity, and stability.Objective:To seek out other superior management avoiding disadvantages associated with the conventional NUM surgery.Method:Three consecutive cases with NUM were treated by a novel two-phase surgical procedure using a commercially available dermal regeneration template; as the first phase, the lesional nail unit was excised and subsequently covered by a dermal regeneration template onto the phalangeal bone surface, allowing development of robust granulation with extracellular matrix and vascular network. Thereafter, the second phase employed a full-thickness skin grafting.Results:All three cases accomplished complete removal of the NUM lesion, and achieved a good cosmetic and functional outcome, maintaining physiological firmness, contour, and less contraction and atrophy of the overlying skin. They did not complain of major post-operative complications.Conclusion:Our two-phase approach using a dermal regeneration material is a satisfactory and straightforward technique, achieving a substantial benefit functionally and cosmetically in the post-operative period. We propose that the additional use of a tissue regeneration material can provide superior results for the reconstruction step of excised NUM.

Nail melanoma in situ: clinical, dermoscopic, pathologic clues, and steps for minimally invasive treatment.

Nail unit melanoma (NUM) is a variant of acral lentiginous melanoma. The differential diagnosis is wide but an acquired brown streak in the nail of a fair-skinned adult person must be considered a potential melanoma. Dermoscopy helps clinicians to more accurately decide if a nail apparatus biopsy is necessary. Detailed evaluation of clinical and dermoscopy features and description of conservative surgery of in situ NUM. Retrospective study of in situ NUM diagnosed and treated with conservative surgical management in the authors' center from 2008 to 2013. Six cases of NUM were identified: 2 male and 4 female patients, age range at diagnosis of 44 to 76 years. All patients underwent complete nail unit removal with at least 6-mm security margins around the anatomic boundaries of the nail. The follow-up varies from 4 to 62 months. Nail unit melanomas pose a difficult diagnostic and therapeutic challenge. Wide excision is sufficient, whereas phalanx amputation is unnecessary and associated with significant morbidity for patients with in situ or early invasive melanoma. Full-thickness skin grafting or second-intention healing after total nail unit excision is a simple procedure providing a good functional and cosmetic outcome.

Dermoscopy of subungual haemorrhage: its usefulness in differential diagnosis from nail-unit melanoma

Subungual haemorrhages are characterized by well-circumscribed dots or blotches with a red to red-black pigmentation, but some cases can be difficult to distinguish from subungual melanoma by the naked eye alone. Dermoscopy has proven to be a useful, noninvasive tool in the diagnosis of pigmented lesions in the nail; however, few dermoscopic studies of subungual haemorrhages have been reported. To investigate characteristic dermoscopic patterns of subungual haemorrhages, and to find distinctive features that can differentiate them from nail-unit melanomas. Patients with a confirmed diagnosis of either subungual haemorrhage or nail-unit melanoma at a tertiary university hospital were included in the study. Clinical features and dermoscopic patterns were evaluated. Sixty-four patients with a total of 90 lesions of subungual haemorrhage were enrolled in the study. The majority of cases (84%) showed combinations of more than one colour, while 16% had only one colour. The most common colour of the subungual haemorrhages was purple-black, in 37% of cases. A homogeneous pattern was observed in 92% of cases, globular patterns in 42% and streaks in 39%. Peripheral fading and periungual haemorrhages were found in 54% and 22% of cases, respectively. Destruction or dystrophy of the nail plate was observed in 16% of cases. In the 16 cases of nail-unit melanomas, Hutchinson sign, longitudinal irregular bands or lines, triangular shape of bands, vascular pattern, and ulcerations were found in 100%, 81%, 25%, 6% and 81% of cases, respectively. In contrast, these features were not found in subungual haemorrhages. Dermoscopy provides valuable information for the diagnosis of subungual haemorrhage and aids in the differential diagnosis from nail-unit melanoma.

In Situ Melanoma of the Nail Unit in Children: Report of Two Cases in Fair‐Skinned Caucasian Children

Nail melanoma in children is rarely reported in the literature, and all of the published cases were diagnosed in dark-skinned phototypes or in Asians. We report two cases of in situ nail matrix melanoma presenting as longitudinal melanonychia (LM) in fair-skinned children of Italian origin. Nail plate dermatoscopy revealed a brown background with lines of irregular color, spacing, and thickness in both cases. Histopathology of the excised lesions showed melanoma in situ. Clinical, dermatoscopic, and pathological criteria that permit clear differentiation of benign melanocytic activation or proliferation from nail matrix melanoma are not established for children. The presence of a pigmented band of a single nail in a child usually represents a problem for clinicians, because the clinical and dermatoscopic features that are considered possible indicators of nail unit melanoma in adults are frequently observed in benign melanocytic hyperplasia and nevi in children. There is therefore the need to find parameters useful for clinical and dermatoscopic diagnosis in childhood nail pigmentation and to reach a consensus on management of children with a band of LM.

Development of a practical guide for the early recognition for malignant melanoma of the foot and nail unit

BackgroundMalignant melanoma is a rare but potentially lethal form of cancer which may arise on the foot. Evidence suggests that due to misdiagnosis and later recognition, foot melanoma has a poorer prognosis than cutaneous melanoma elsewhere.MethodsA panel of experts representing podiatry and dermatologists with a special interest in skin oncology was assembled to review the literature and clinical evidence to develop a clinical guide for the early recognition of plantar and nail unit melanoma.ResultsA systematic review of the literature revealed little high quality data to inform the guide. However a significant number of case reports and series were available for analysis. From these, the salient features were collated and summarised into the guide. Based on these features a new acronym "CUBED" for foot melanoma was drafted and incorporated in the guide.ConclusionsThe use of this guide may help clinicians in their assessment of suspicious lesions on the foot (including the nail unit). Earlier detection of suspicious pedal lesions may facilitate earlier referral for expert assessment and definitive diagnosis. The guide is currently being field tested amongst practitioners.

Dermoscopy as a technique for the early identification of foot melanoma

Malignant melanoma is the most common primary malignant tumour arising on the foot. Where improvements in the prognosis have been observed for patients with melanoma elsewhere on the skin, pedal lesions are still frequently delayed in presentation through neglect or misdiagnosis. Detection of foot melanoma relies on the health care practitioner's skills and observations in recognising early changes. Recent publications have documented the use a dermoscopy as a tool to improve recognition of such suspicious lesions. This paper reviews current literature with a special emphasis of its potential applications on plantar and nail unit melanoma. Data from these studies suggest that the technique is a useful and significant adjunct to clinical examination, which ultimately may lead to earlier recognition of this aggressive tumour.