Nail apparatus melanoma

Subungual melanoma: molecular analysis of 31 cases from early stage to invasive melanoma

AIMS

The distinction between the benign subungual melanocytic lesions and an early lesion of subungual melanoma (SUM) remains a diagnostic challenge. We evaluated the routine diagnostic utility of array Comparative Genomic Hybridization (aCGH) to detect whole-genome copy number variations (CNV) as well as targeted next-generation sequencing (NGS) in SUM.

METHODS AND RESULTS

This retrospective study included 20 cases of in situ SUM and 11 cases of invasive SUM. Analysis by aCGH detected common oncogene amplifications in all but one case of invasive SUM (n = 10) and in all cases of in situ SUM with a melanocyte count (MC) >45/mm (n = 4 true positive) and the average number of CNV was 8.5. Thirteen remaining cases of in situ SUM gave false negative results (n = 13), owing to a lack of sufficient melanocytes to analyse (median MC of 35.35; range: 10.16-39.5). Molecular analysis failed in four cases (three in situ SUM and one invasive SUM) due to insufficient amounts of DNA. Across the whole cohort, the sensitivity of aCGH was 52%, but when adjusting the cutoff to MC >45/mm, the sensitivity was 93%. Targeted NGS was less informative than aCGH analyses in our series of SUM.

CONCLUSION

To distinguish malignant from benign lesions, especially in situ SUM versus atypical lentiginous melanocytic proliferations, aCGH analysis should be performed when the MC is above 45 melanocytes per linear millimetre. This pangenomic method can detect oncogene amplifications, as well as a number of CNV >3, which strongly support the diagnosis of malignancy.

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.

Seven Plus One Steps to Assess Pigmented Nail Bands (Melanonychia Striata Longitudinalis)

Melanonychia striata longitudinalis might involve one or more fingers and/or toes and might result from several different causes, including benign and malignant tumors, trauma, infections, and activation of melanocytes that might be reactive or related to the pigmentary trait, drugs and some rare syndromes. This broad differential diagnosis renders the clinical assessment of melanonychia striata particularly challenging. Nail matrix melanoma is relatively rare, occurs almost always in adults involves more frequently the first toe or thumb. The most common nail unit cancer, squamous cell carcinoma / Bowen disease (SCC) of the nail matrix is seldom pigmented. Histopathologic examination remains the gold standard for melanoma and SCC diagnosis, but excisional or partial biopsies from the nail matrix require training and is not routinely performed by the majority of clinicians. Furthermore, the histopathologic evaluation of melanocytic lesions of the nail matrix is particularly challenging, since early melanoma has only bland histopathologic alterations. Dermatoscopy of the nail plate and its free edge significantly improves the clinical diagnosis, since specific patterns have been associated to each one of the causes of melanonychia. Based on knowledge generated and published in the last decades, we propose herein a stepwise diagnostic approach for melanonychia striata longitudinalis: 1) Hemorrhage first 2) Age matters 3) Number of nails matters 4) Free edge matters 5) Brown or gray? 6) Size matters 7) Regular or irregular and, finally, "follow back".

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.

The pharmacotherapeutic management of nail unit and acral melanomas

INTRODUCTION

Acral and nail unit melanomas are rare subtypes of melanoma, which have poor prognoses. Current guidelines for optimal treatment are lacking. Recent clinical trials have evaluated new pharmacotherapeutic agents for melanoma treatment, with dramatically improved survival rates; however, studies on acral and nail unit melanomas are limited in comparison to trials on cutaneous melanoma.

AREAS COVERED

This is a comprehensive review of the literature regarding the available treatment options for acral and nail unit melanomas, with consideration of safety and tolerability.

EXPERT OPINION

Programmed cell death protein 1 inhibitors are more efficacious than cytotoxic T lymphocyte-associated antigen-4 blockers in acral and nail unit melanomas, although both are well-tolerated. Tyrosine kinase inhibitors have good clinical activity, however, data on safety is relatively limited. There is minimal data on high dose interferon α-2b and cyclin-dependent kinase 4 and 6 inhibitors, and efficacy and safety must be evaluated in future trials before they can be recommended for use in this patient population. Prospective clinical trials on acral and nail unit melanomas are lacking, and must be performed in large patient populations, with international collaboration likely necessary in order to enroll adequate participants.

Subungual melanoma with blue naevus-like morphological features: a clinicopathological retrospective analysis of nine cases

Melanocytic lesions in the nail apparatus are often challenging. Both subungual melanomas (SUM) and blue naevus of the nail are very rare. Occasionally, melanomas may mimic blue naevus histologically. Benign and malignant blue melanocytic lesions are commonly associated with G protein mutations, a distinct abnormality not associated with conventional subungual melanomas. We describe the clinical, histological and immunohistochemical features of nine cases of SUM with blue naevus-like morphological features. Mutations in exon 4 and 5 of GNAQ and GNA11 were investigated in two cases, which showed no mutations. RNA-seq of one case revealed unknown mutations along with mutations in ATM, METK and ARID1A. Our study delineates a variant of SUM that mimics blue naevus. Awareness of this pitfall is important when evaluating heavily pigmented lesions around the nail in order to avoid misdiagnosis. Appropriate sampling of subungual lesions and clinicopathological correlation are paramount to reach the correct diagnosis.

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.

Clinical and Onychoscopic Features of Benign and Malignant Conditions in Longitudinal Melanonychia in the Thai Population: A Comparative Analysis

Background

Longitudinal melanonychia can arise from many underlying conditions, both benign and malignant. Practitioners tend to be reluctant to perform a biopsy of this condition due to procedure-related pain and the possibility of permanent nail dystrophy. Onychoscopy has become a useful tool to provide a provisional diagnosis and assist in deciding on a nail biopsy.

Objective

To investigate and differentiate the clinical and onychoscopic features of subungual melanoma (SUM)/subungual melanoma in situ (SMIS) and other benign melanocytic conditions (BM).

Materials and Methods

In this cross-sectional study, a total of 32 cases of longitudinal melanonychia were examined, and baseline characteristics were recorded. Onychoscopic pictures were taken by handheld dermoscopy with 10x and 50x magnification. A biopsy was then performed in each case, and a pathological diagnosis was obtained.

Results

Of the 32 cases, 6 were diagnosed with SMIS and 26 with BM (21 simple lentigines, 5 junctional nevi). The median age was significantly higher among the SMIS group (56 vs 31 years) (p = 0.034). Regarding onychoscopic findings, cases with SMIS were significantly associated with a greater band width percentage (p = 0.014), multicolor presentation (p = 0.005), the presence of granular pigmentation (p = 0.034), and micro-Hutchinson’s sign (p = 0.015). In addition, subungual hyperkeratosis, a newly recognized onychoscopic feature, was more significantly associated with SMIS in comparison to BM (p = 0.002).

Conclusion

Onychoscopy provides useful information to aid in the differential diagnosis of longitudinal melanonychia. From our study, onychoscopy can be utilized to assist in making a decision whether to perform a biopsy in patients with longitudinal melanonychia suspicious of malignant melanocytic conditions.

Melanonychia: Etiology, Diagnosis, and Treatment

Melanonychia is a very worrisome entity for most patients. It is characterized by brownish black discoloration of nail plate and is a common cause of nail plate pigmentation. The aetiology of melanonychia ranges from more common benign causes to less common invasive and in situ melanomas. Melanonychia especially in a longitudinal band form can be due to both local and systemic causes. An understanding of the epidemiology, pathophysiology and clinical details is necessary for adequate patient care and counseling. It not only helps in the early recognition of melanoma but also prevents unnecessary invasive work up in cases with benign etiology. An early diagnosis of malignant lesion is the key to favourable outcome. Though there are no established guidelines or algorithms for evaluating melanonychia, a systematic stepwise approach has been suggested to arrive at a probable etiology. We, hereby, review the aetiology, clinical features, diagnostic modalities and management protocol for melanonychia.

The color of skin: black diseases of the skin, nails, and mucosa

Gradations in skin color are a consequence of differing amounts of melanin and their varying distribution. Although many darkly pigmented skin lesions are melanocytic and can be attributed to melanin content, the color of a black lesion can also be due to blood, necrotic tissue, or exogenous pigment. The source, pattern, and distribution of the color in black lesions usually offer important insight into its etiology. This contribution reviews conditions that can take on a black color, discussing the cause of the hue and any additional impact sun exposure may have.

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.

Treatment of Digital Melanonychia with Atypia

BACKGROUND

Melanonychia of the digit is uncommon in the Caucasian population and is concerning because of potential malignant transformation. Several histologic changes occur before malignant transformation, including melanocytic atypia. The authors evaluated patients with melanonychia with melanocytic hyperplasia to determine the risk factors for malignant transformation.

METHODS

The authors retrospectively reviewed records for patients older than 18 years that underwent biopsy for melanonychia. They identified 22 patients with melanocytic hyperplasia with a median age of 61 years (interquartile range, 44 to 71 years). A bivariate analysis was performed to evaluate whether the degree of atypia was associated with malignant transformation and whether treatment choices by surgeons were based on melanocytic atypia.

RESULTS

Following biopsy, patients were followed for a median of 41.0 months (interquartile range, 4.8 to 100.6 months). Melanocytic atypia was present in nine patients and transformed into a malignancy in three: in two patients it became a melanoma in situ, and in one it became an acral lentiginous melanoma. Moderate-severe and severe melanocytic atypia was associated with malignant transformation. After initial biopsy, 14 patients were monitored (11 without atypia and three with atypia). One patient with slight atypia, two patients with moderate-severe atypia, and two patients with severe atypia underwent additional treatment. Patients with melanocytic hyperplasia without atypia were monitored more often (78.6 percent versus 21.4 percent).

CONCLUSIONS

Melanonychia presents a challenge to the hand surgeon, as some patients may be monitored and some should undergo additional resection. Patients with moderate-severe melanocytic atypia following biopsy should undergo resection, and those with mild to slight atypia can most often be monitored clinically.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Nodular melanoma presenting as an exophytic subungual mass

Despite being recognised and reported in the literature for decades, subungual melanoma of the foot remains a diagnostic pitfall, with it commonly being mistaken for benign conditions. We present an interesting case of delayed diagnosis of subungual melanoma of the hallux that was misdiagnosed in the community for over one year. With melanoma being the fourth most commonly diagnosed cancer in Australia in 2013, this case serves as a reminder to all clinicians about the importance of maintaining a high index of suspicion for melanoma of the foot.

Nail neoplasms

Nail neoplasms include all tumors occurring in the nail or periungual apparatus tissue. While some nail tumors can be similar to tumors located on the skin, others are unique. Both benign and malignant lesions can affect the nail apparatus. In particular, early malignant tumors like melanoma and squamous cell carcinoma can present similarly to onychomycosis or benign melanonychia and frequently missed by clinicians. Therefore, physicians should be aware of nail structures and the characteristics of nail tumors. Our review covers the normal nail structure and the most common nail tumors from benign to malignant.

Clinical and dermoscopic clues to differentiate pigmented nail bands: an International Dermoscopy Society study

BACKGROUND

Longitudinal melanonychia might be difficult to differentiate and the use of dermoscopy can be useful for the preoperative evaluation and management decision.

OBJECTIVES

The aim of our study was to investigate clinical and dermoscopic criteria of acquired longitudinal melanonychia in adults to identify the best predictors of melanoma using a multivariate analysis and to explore eventual new dermoscopic criteria for nail melanoma diagnosis.

METHODS

In this retrospective observational study, 82 histopathologically diagnosed, acquired nail pigmented bands were collected and examined. All variables were included in the analysis and examined as possible predictors of nail melanoma. Both univariate and multivariable analyses have been performed.

RESULTS

Among 82 cases, 25 were diagnosed as nail melanoma and 57 as benign lesions (including 32 melanocytic nevi and 25 benign melanocytic hyperplasia). Melanoma cases were significantly associated with a width of the pigmented band higher than 2/3 of the nail plate, grey and black colours, irregularly pigmented lines, Hutchinson and micro-Hutchinson signs, and nail dystrophy. Granular pigmentation, a newly defined dermoscopic criterion, was found in 40% of melanomas and only in 3.51% of benign lesions.

CONCLUSIONS

Dermoscopic examination of longitudinal melanonychia provides useful information that could help clinicians to improve melanoma recognition.

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.

Guidelines of the Brazilian Dermatology Society for diagnosis, treatment and follow up of primary cutaneous melanoma--Part I

The last Brazilian guidelines on melanoma were published in 2002. Development in diagnosis and treatment made updating necessary. The coordinators elaborated ten clinical questions, based on PICO system. A Medline search, according to specific MeSH terms for each of the 10 questions was performed and articles selected were classified from A to D according to level of scientific evidence. Based on the results, recommendations were defined and classified according to scientific strength. The present Guidelines were divided in two parts for editorial and publication reasons. In the first part, the following clinical questions were answered: 1) The use of dermoscopy for diagnosis of primary cutaneous melanoma brings benefits for patients when compared with clinical examination? 2) Does dermoscopy favor diagnosis of nail apparatus melanoma? 3) Is there a prognostic difference when incisional or excisional biopsies are used? 4) Does revision by a pathologist trained in melanoma contribute to diagnosis and treatment of primary cutaneous melanoma? What margins should be used to treat lentigo maligna melanoma and melanoma in situ?

The nail dermis: from microanatomy to constitutive modelling

AIMS

The nail mesenchyme, as ligamentous connective tissue, is classically described as a single compartment. Some authors have even suggested the concept of the nail as a musculoskeletal appendage. Recent studies conducted on supernumerary digits surgically removed for polydactyly or on the developing nail organ have introduced into the literature a new concept: the onychodermis and its onychofibroblasts that are CD10-positive/CD34-negative. The aim of this study was to explore the nail mesenchyme more comprehensively.

METHODS AND RESULTS

A series of 10 normal adult nail units were examined with a combination of morphological and immunohistochemical analysis. This study demonstrates that the nail mesenchyme has two distinct compartments, with a complex microanatomy of matrical dermis and its hypoderm. The matrical dermis is a relatively independent substructure, and comprises two parts: a thin papillary dermis, and a relatively thick reticular dermis. The matrical hypoderm corresponds to a cushion-like layer of adipose tissue, which distally intermingles with an area of loose connective tissue. The nail bed dermis comprises a single, relatively homogeneous compartment.

CONCLUSION

The matrical nail mesenchyme is a modified dermis. The concept of onychodermis is not applicable in the normal adult nail. Underrecognized non-pathological structures may pose diagnostic problems. The chameleon matrical hypoderm is one such structure.

Acquired melanonychia in chilean patients with essential thrombocythemia treated with hydroxyurea: a report of 7 clinical cases and review of the literature

Longitudinal melanonychia has been associated with a range of drugs, especially chemotherapeutic agents. We report 7 cases of melanonychia associated with the use of hydroxycarbamide for essential thrombocythemia. Of a patient population of 27, 7 (26%) developed melanonychia over a period of 2-7 years, and was not dose dependent. The high incidence of melanonychia in Chilean patients may be in part due to their Hispanic descent or to the high levels of UV radiation found in Santiago.

Key point in dermoscopic differentiation between early nail apparatus melanoma and benign longitudinal melanonychia

Longitudinal melanonychia presents in various conditions including neoplastic and reactive disorders. It is much more frequently seen in non-Caucasians than Caucasians. While most cases of nail apparatus melanoma start as longitudinal melanonychia, melanocytic nevi of the nail apparatus also typically accompany longitudinal melanonychia. Identifying the suspicious longitudinal melanonychia is therefore an important task for dermatologists. Dermoscopy provides useful information for making this decision. The most suspicious dermoscopic feature of early nail apparatus melanoma is irregular lines on a brown background. Evaluation of the irregularity may be rather subjective, but through experience, dermatologists can improve their diagnostic skills of longitudinal melanonychia, including benign conditions showing regular lines. Other important dermoscopic features of early nail apparatus melanoma are micro-Hutchinson's sign, a wide pigmented band, and triangular pigmentation on the nail plate. Although there is as yet no solid evidence concerning the frequency of dermoscopic follow up, we recommend checking the suspicious longitudinal melanonychia every 6 months. Moreover, patients with longitudinal melanonychia should be asked to return to the clinic quickly if the lesion shows obvious changes. Diagnosis of amelanotic or hypomelanotic melanoma affecting the nail apparatus is also challenging, but melanoma should be highly suspected if remnants of melanin granules are detected dermoscopically.

Cutaneous malignancies: melanoma and nonmelanoma types

This article reviews melanoma and nonmelanoma cutaneous malignancies.

Clinical pathologic correlations for diagnosis and treatment of nail disorders

Clinicopathologic correlation is crucial to the correct diagnosis of disorders of the nail unit. This chapter will explore four common clinical scenarios and how pathology can help differentiate between their various etiologies. These include: dark spot on the nail plate (melanin versus heme), subungual hyperkeratosis (onychomycosis versus psoriasis), longitudinal melanonychia (benign versus malignant), and verrucous papule (verruca versus squamous cell carcinoma). Consideration must be given to both when to perform a biopsy and the location of the biopsy site, which must be based on an understanding of the origin of the changes. An overarching principle is that lesions within the same differential diagnosis may be present concomitantly, such as malignant melanoma of the nail unit associated with hemorrhage. Therefore, even with a biopsy-proven diagnosis, the clinician must always monitor lesions of the nail unit for appropriate response to treatment and consider an additional biopsy for recalcitrant lesions.

Pigmented nail disorders

Nail pigmentation is defined by the presence of melanin in the nail plate. It most frequently has the appearance of a longitudinal pigmented band, called longitudinal mel-anonychia (LM). LM is an important aspect of ungual pathology because it can be the first sign of nail apparatus melanoma. The aim of this article is to help distinguish those types of melanonychia that are worrisome and should lead to biopsy from those that are reasonably reassuring and need only be followed clinically. Histology, differential diagnosis, and biopsy techniques also are considered.

Concomitant traumas influence prognosis in melanomas of the nail apparatus*

BACKGROUND

In nail apparatus melanomas (NAM), the role of standard melanoma prognostic factors is under discussion. The prognostic influence of traumas to the clinically apparent tumour has not been sufficiently examined.

OBJECTIVES

To estimate the influence of traumas against the background of standard prognostic factors on the course of NAM.

METHODS

In 33 patients (20 women, 13 men, median age 65.0 years) with NAM (median tumour thickness 3.5 mm), we retrospectively examined a detailed history of trauma to the affected extremity at first presentation. Histological or other standard prognostic factors and follow-up were studied prospectively using a standardized protocol.

RESULTS

Of 33 patients, 21 had suffered injury to the clinically apparent melanoma primary between 4 and 72 months prior to definitive surgical treatment (diagnostic biopsy up to 3 months ahead of excision of the melanoma was not considered). Eight of these patients had undergone inadequate therapy procedures. In Kaplan-Meier analysis, trauma to the clinically apparent tumour and tumour thickness were found to be significant prognostic factors for recurrence-free survival, and trauma to the clinically apparent tumour, Clark level and tumour thickness were significant prognosis predictors for overall survival. In Cox's proportional hazards model, trauma to the clinically apparent tumour was found to be a significant and independent risk factor with regard to overall survival (hazard ratio 5.39; P = 0.029). An influence of trauma on the primary pathogenesis of NAM could not be confirmed. Only three patients reported trauma prior to the onset of tumour.

CONCLUSIONS

From our data, trauma to the clinically apparent tumour might be a considerable risk factor in NAM. The diagnosis of NAM should be considered in lesions of the nail apparatus and further deterioration of the prognosis due to inadequate therapeutic attempts or injury to the NAM should be avoided.