Consensus on melanonychia nail plate dermoscopy

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.

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.

Clinical and dermoscopic findings of benign longitudinal melanonychia due to melanocytic activation differ by skin type and predict likelihood of nail matrix biopsy

BACKGROUND

Longitudinal melanonychia (LM) is a common dermatologic finding in clinical practice with a broad differential diagnosis. Melanocytic activation is the most common LM etiology.

OBJECTIVE

To investigate clinical and dermoscopic differences of benign LM based on Fitzpatrick skin type and in biopsied vs. non-biopsied patients.

METHODS

A 10-year retrospective cohort of 248 benign LM cases at Weill Cornell Dermatology was identified and analyzed.

RESULTS

Darker-skinned vs. lighter-skinned patients had higher band width percentage (p=0.0125), lower band brightness (p<0.001), more band changes (p=0.0071), and received more biopsies (p=0.032). Biopsied (n=47) vs. non-biopsied patients (n=201) had less multidigit band involvement (p=0.0008), higher band width percentage (p=0.0213), lower band brightness (p=0.0003), and more band changes (p<0.0001). Darker skin types more often had brown vs. grey coloration on dermoscopy (p=0.0232). Mean band width percentage for all biopsied patients was 30.81% (range: 5.80%-100%).

LIMITATIONS

Single-center retrospective design. Subungual melanoma and other benign LM etiologies were not analyzed. Only 18.95% of patients received a biopsy.

CONCLUSION

Darker vs. lighter skin types more often present with darker and wider bands, brown vs. grey coloration on dermoscopy, and receive more biopsies. Multi-institutional studies on LM are needed to determine nail matrix biopsy criteria in different skin types.

Mimical reconstruction and aesthetic repair of the nail after resection of subungual melanocytic nevus

Background

This study aimed to report the outcomes of mimical reconstruction and aesthetic repair of the nail.

Methods

When the pigmented bands were more than 1/2 the width of the whole nail, mimical reconstruction of the nail was performed, with a lateral toe pulp island flap covering the wound via the subcutaneous channel. If the pigmented bands were 1/4 to 2/5 the width of the entire nail, aesthetic repair of the nail was carried out by split-thickness excision under a microscope.

Results

The average age of patients at the time of surgery was 14.5 years. Five patients had lesions on their toes, while three had lesions on their fingers. There were no post-operative complications. All toenails of the five patients who had undergone mimical reconstruction exhibited a well-settled flap. The nails of the three patients who underwent aesthetic repair displayed no nail malnutrition or deformity, and all nails had an aesthetic appearance.

Conclusions

Both mimical reconstruction and aesthetic repair of the nail following resection of subungual melanocytic nevus are reliable and feasible. The “like tissue” repairs of complex nail defects appear to be satisfactory. All patients had excellent aesthetic outcomes.

Level of evidence

V

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01423-9.

An Evidence-Based Approach to Pediatric Melanonychia

Melanonychia including melanonychia striata in children poses a diagnostic dilemma. Atypical clinical features often raise the possibility of malignancy, and a nail unit biopsy may be recommended. Commensurate with atypical clinical features, the histopathology may also appear alarming. However, accumulating data illustrate that most cases of melanonychia striata are benign and suggest that an alternate approach is often warranted for pediatric patients. Herein, we review the existing data regarding pediatric melanonychia striata and offer an evidence-based approach to its evaluation and management.

Dermoscopic Evaluation of Longitudinal Melanonychia in Children: A Prospective Study

Background:

Longitudinal melanonychia (LM) is a worrisome sign in both children and adults. Nail apparatus melanoma (NAM) can be related to LM, but it is very rare in children. Dermoscopic signs of benign lesions in children can be similar to melanoma; therefore, it is important to review dermoscopy of LM in children to make the best decision in performing biopsy.

Aims:

Biopsy taking is very challenging in LM in children. Most lesions are benign in children. The aim of this study was to review dermoscopic signs of LM in children and compare them with adults.

Materials and Methods:

In this prospective study a total of 108 LM (35 children and 73 adults) were undergone dermoscopy of LM. Dermoscopic features were compared in children and adults; both for benign lesions proven by biopsy or follow up and melanomas diagnosed histopathologically.

Results:

Black background, black band color, band color diversity and pseudo-Hutchinson's sign were more frequent in children in comparison with benign adult melanonychia. Some children's dermoscopic features of LM such as broad band width, Band color diversity, Hutchinson's sign, gray band color, asymmetry of pattern, and regression were similar to melanoma, but we did not find any melanoma by biopsy and/or follow up among children. We also detected the newly described "zigzag" pattern in four children.

Conclusion:

Dermatologists should consider all dermoscopic features of a lesion, dermoscopic sign changes in follow-up, medical, and familial history of the patient in deciding to perform biopsy of LM in children.

Dermoscopic features of neoplasms in skin of color: A review

BACKGROUND

Dermoscopy is undoubtedly a useful tool to improve diagnostic accuracy and minimize the number of unnecessary biopsies. However, much of the literature on dermoscopy focuses on findings in lighter-skin phototypes, leaving potential gaps of knowledge regarding its use in skin of color (SoC). As the clinical applications of dermoscopy continue to increase, understanding dermoscopic patterns in SoC is imperative.

OBJECTIVE

This review discusses the literature on dermoscopic findings of neoplasms in SoC, highlighting unique and characteristic dermoscopic features.

METHODS

A literature review was performed using the PubMed database. Case reports, case series, case-control studies, and systematic reviews were included.

RESULTS

A total of 8326 studies were identified based on the selected search terms, and 41 were included in this review based on relevance.

CONCLUSION

There are specific dermoscopic characteristics in SoC for benign nevi, acral lentiginous melanoma, ethnic melanonychia, and dermatofibroma; however, there is a lack of published data about specific features of cutaneous melanoma, subungual melanoma, pigmented basal cell carcinoma, and pigmented squamous cell carcinoma in SoC. Because pigmented basal cell carcinoma, pigmented squamous cell carcinoma, ethnic melanonychia, and acral lentiginous melanoma are diagnosed at later stages in this population, it is important to understand their dermoscopic features. Further descriptive studies are needed to better characterize unique dermoscopic features in neoplasms in SoC.

Diagnosis of Melanonychia

Melanonychia has many causes and can involve one or several fingernails or toenails, and may occur at any age. Dermoscopy is used routinely in the evaluation of a pigmented nail. If pigmentation is caused by melanin produced by nail matrix, identify whether the pigmentation is caused by an activation or proliferation of nail melanocytes. When melanocytic proliferation is suspected, biopsy with histopathologic examination is the gold standard for diagnosis and is recommended when a longitudinal melanonychia occurs in an adult and is localized in a single digit, in the absence of local or systemic causes that may explain its onset.

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.

Intra-Operative Dermoscopy in Assessment of Melanonychia and as a Guide for Biopsy

Background and Aims:

Melanonychia can be a manifestation of benign or malignant pathology and often poses a diagnostic challenge on clinical examination. Even with distinguishing dermoscopic features (nail plate), it can be quite difficult to determine the nature of pigmentation as complete assessment of nail bed and matrix is still not possible. Intraoperative dermoscopy (IOD) can serve as a useful tool to appreciate the bed and matrix changes. The aim here is to study the intraoperative dermoscopic features in patients with melanonychia and correlate with histopathology.

Methods:

20 consecutive patients with melanonychia were recruited. Inclusion criteria was melanonychia of sudden onset, progressive nature, irregular width/color/symmetry on dermoscopy, positive Hutchinson sign, solitary nail involvement or associated nail dystrophy. Preoperative dermoscopy was performed and recorded. Patients were planned for nail matrix biopsy, during which IOD was performed over nail matrix and bed after removal of the nail plate. Images were recorded and analyzed and correlated with the histopathology.

Results:

Out of 20 patients, 12 were females and 8 males. On IOD-histopathological correlation, 2 patients were found to have melanoma of the nail unit, 5had nail lichen planus, 9 had benign melanocytic nevi, and 4 had fungal melanonychia. IOD revealed fine, parallel and regular lines of pigmentation localized to proximal nail bed and matrix in all patients with benign melanonychia, while dark thick bands with irregular borders, dots, globules, streaks and structureless areas in the two patients with melanoma. Fungal melanonychia revealed an unremarkable nail bed and matrix on IOD.

Conclusion:

Intraoperative dermoscopycan help in determining the nature of melanonychia and obviate the need to perform biopsy in certain cases. It can also aid in delineating the most suitable site for biopsy, along with grossly assessing the extent of involvement in case of malignancy.

Subungual Hematoma with Feline Resemblance

A 54-year-old woman was found to have an incidental pigmented lesion on her right thumbnail. Interestingly, this lesion was in the shape of a cat and she also had a cat tattoo. We briefly review how coincidences have been known to occur in dermatology. We also highlight how dermoscopy can aid in differentiating pigmented lesions from trauma-induced changes.

The causes of nail apparatus pigmentation presenting to a melanoma screening clinic a prospective study

BACKGROUND

Advanced stage primary cutaneous malignant melanoma (PCMM) has a high mortality. PCMM may affect any area of the skin, including the nail apparatus (malignant melanoma or subungual melanoma). Although nail apparatus malignant melanoma (NAMM) is rare, delayed diagnosis carries a poor prognosis.

AIM

The primary aim was to study the range of nail presentations and identify key patterns to aid in differential diagnosis. A secondary aim was to quantify the number of patients requiring surgery, indications for biopsy, and the incidence and characteristics of NAMM.

METHODS

This was a prospective study of all referrals with nail apparatus pigmentation to a weekly dedicated melanoma screening clinic over a 6-month period.

RESULTS

In total, 2246 patients were included. Of the 38 patients referred with nail pigmentation, 1 (2.6%) was diagnosed with NAMM and involved a fungating amelanotic lesion of the right hallux. The remaining patients were diagnosed with subungual haematoma (20/38; 52.6%), viral wart (2/38; 5.4%), acral fibrokeratoma (1/38; 2.6%), myxoid cyst (3/38; 7.9%), fungal nail infection (4/38; 10.5%), Pseudomonas nail infection (1/38; 2.6%), benign linear pigmentation (2/38, 5.3%), Bowen disease (1/38, 2.6%), psoriatic nail changes (2/38; 5.3%) and matrix malalignment (1/38; 2.6%). Of the eight patients (21.1%) who required surgery, five had a biopsy taken and three underwent surgery. Only 14 cases were followed up by Dermatology. NAMM accounted for 0.7% of all melanomas diagnosed.

CONCLUSION

We illustrate the wide range of diagnoses for pigmented nail presentations and highlight the late presentation of advanced disease in a patient presenting with NAMM.

The Importance of Dermatoscopy for the Diagnosis of Melanonychia

Melanonychia is the brown or black color of the finger or toe nail due to melanin deposition or melanocytes in the nail plate. The evidence of melanocytic disease is made by the dermatoscope, which allows to highlight the anomalies of the plate. The purpose of our study was to evaluate dermatoscopically the melanonychia, both in the form of stain and longitudinal on finger and/or toe nails in order to establish the type of nail hyperpigmentation.

MATERIALS AND METHOD

33 patients with longitudinal and stain melanonychia were examined with 30x Molemax HD computerized dermatoscope between May 2017-septembre 2018 in this prospective study conducted in the Department of Dermatology of Medical Center Dr. Ianosi (Craiova, Romania). Clinical data included: type of melanonychia, number and name of involved fingers, the presence or absence of fungal infections, nail apparatus tumors or hemorrhage.

RESULTS

The most frequent nail diagnosis was fungal infection (onychomycosis) observed in 18 patients (54.54%), malignant melanoma was diagnosed in 1 patient (3.03%) and the junctional nevus in 4 patients (12.12%). In 18 patients which has longitudinal melanonychia, the most frequent involved finger was the big toe, and in 15 patients which has stain melanonychia, all of them (100%) had affected the big toe, 7 (46.66%) patients had affected the thumb and the same percent the forth finger.

CONCLUSION

Nail dermatoscopy is an important method in establishing the diagnosis of melanonychia and allowed to avoid unnecessary biopsy for melanonychia.

Use of Nail Dermoscopy in the Management of Melanonychia: Review

The term melanonychia describes a black-brown-gray pigmentation of the nail plate that, in most cases, appears as a longitudinal band. Melanonychia can be observed at any age, affecting one digit or several digits, in both fingernails and toenails. Its causes can be difficult to differentiate clinically and depend on the number of bands and on their color, edge, and width. For this reason, especially in adults and when the pigmentation is localized in one single digit, biopsy and histopathological examination still represent the gold standard for a definitive diagnosis. Dermoscopy should be used routinely in the evaluation of a pigmented nail, as it provides important information for the management of melanonychia and can help avoid unnecessary nail biopsies. In cases of melanonychia it is important to establish whether the pigment is melanin or not and to determine whether the pigmentation of melanin is due to activation or proliferation and whether it is benign or malignant.

Dermoscopy in the Evaluation of Nail Disorders

Nail dermoscopy was initially used only in the assessment of nail pigmentation, but now it is widely utilized for the evaluation of many nail disorders. In daily practice, dermoscopy may confirm clinical diagnoses and guides in the management of nail diseases and treatments, permitting a better visualization of symptoms. Dry dermoscopy is required for evaluation of the nail plate surface, while gel as an interface is necessary for assessment of nail pigmentation and onycholysis, as well as for the evaluation of the distal nail margin. In this review, we describe the dermoscopic features of the most important nail disorders, looking at the different areas of the nail. Dermatoscopic changes that usually accompany specific nail diseases are also reviewed.

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.

Dermoscopy of difficult-to-diagnose Melanomas

Dermoscopy is a non-invasive procedure that allows the evaluation of cutaneous lesions, and is considered to be a useful tool that improves the diagnostic accuracy of melanoma. Many dermoscopic criteria of melanoma have been established and several algorithms have been created for melanoma detection. However, the recognition of some melanomas remains challenging. Melanomas on specific body sites, melanomas in patients with multiple atypical moles, and nodular melanomas represent the most difficult-to-recognize melanoma subtypes, since they typically lack the “classic” melanoma-specific criteria. This paper provides an update on dermoscopy of difficult-to-diagnose melanomas by summarizing the newest data. Lastly, we highlight the importance of digital dermoscopy in the follow-up of melanocytic lesions for the detection of incipient melanomas while maintaining a low excision rate.

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?

Longitudinal melanonychia in an Iranian population: a study of 96 patients

Background

Longitudinal melanonychia (LM) can be a challenging sign since it may be caused by a wide variety of benign and malignant conditions. Cutaneous melanoma is the most important cause of LM. Objective: We performed this study to examine different aspects of LM in Iran, where cutaneous melanoma is rare.

Methods

In this cross-sectional study, we reviewed medical records and pathology reports of a total of 96 patients presenting with LM. These patients had been visited and undergone nail biopsy in Razi Hospital, Tehran University of Medical Sciences, Tehran, Iran. Demographic, clinical, and pathological data were recorded.

Results

The most common diagnosis was junctional nevi in 28 patients (29.2%) followed by melanoma in 19 patients (19.8%). Patients had a mean age of 42.4 years (± 19.4). The mean ages in the groups with junctional nevi and melanoma were 33.3 (± 19.5) and 51.9 (± 17.8), respectively; their difference was statistically significant (P value = 0.001). Hutchinson’s sign was present in 10 patients, 9 of which had melanoma. Also, melanoma was only observed in patients presenting with a solitary nail lesion. Nails mostly affected by melanoma were middle fingers of the hands (7 patients) and thumbs (6 patients). Out of 18 patients with nail dystrophy, 13 (72.2%) were diagnosed with melanoma.

Limitations

Only patients who have undergone biopsy were studied.

Conclusion

Melanoma is an important cause of LM in Iranian patients and should especially be suspected in older patients who present with a solitary nail lesion on their middle finger or thumb. Other findings that direct us toward melanoma are presence of Hutchinson’s sign and nail dystrophy.

Onychomatricoma: a tumor unknown to dermatologists

A sixty-one year old white female was referred to the Dermatology Department to treat an ingrown nail in the inner corner of the left hallux. Examination of the entire nail unit showed the presence of xanthonychia in the outer corner besides thickening and increase in the transverse curvature of the nail plate. Dermoscopy and nuclear magnetic resonance of the free edge of the nail plate detected characteristic signs of onychomatricoma, a diagnosis that was later confirmed by anatomopathological exam.

Tips for diagnosis and treatment of nail pigmentation with practical algorithm

The observation of a black-brown pigmentation of the nail is often alarming for the patient and for the clinician, as they are aware that it can be a possible clinical manifestation of melanoma of the nail apparatus. Luckily, however, nail melanoma is a much less frequent cause of brown-black nail color than other melanocytic and nonmelanocytic pigmentations, which include subungual hematoma, exogenous pigmentations, and melanonychia due to benign conditions. A correct clinical history and careful examination help the clinician to distinguish the different conditions and to decide the correct management of melanonychia both in children and in adults.

[Malignant nail tumors]

Because of the large number of different tissues making up the distal phalanx of fingers and toes, a large variety of malignant tumors can be found in and around the nail apparatus. Bowen disease is probably the most frequent nail malignancy. It is usually seen as a verrucous plaque of the nail fold and nail bed in persons above the age of 40 years. It slowly grows over a period of years or even decades before degenerating to an invasive squamous cell carcinoma. The latter may also occur primarily often as a weeping onycholysis. The next most frequent nail malignancy is ungual melanoma. Those arising from the matrix are usually pigmented and often start with a longitudinal melanonychia whereas those originating from the nail bed remain amelanotic, are often nodular and mistaken for an ingrown nail in an elderly person. The treatment of choice for in situ and early invasive subungual melanomas is generous extirpation of the nail apparatus whereas distal amputation is only indicated for advanced melanomas. In addition to these frequent nail malignancies, nail-specific carcinomas, malignant vascular and osseous tumors, other sarcomas, nail involvement in malignant systemic disorders and metastases may occur. In most cases, they cannot be diagnosed accurately on clinical grounds. Therefore, a high degree of suspicion is necessary in all isolated or single-digit proliferations that do not respond to conservative treatment.

Diagnosis and management of nail disorders in children

The authors herein describe several nail conditions, which the general pediatrician is likely to encounter in the course of routine practice. Because pediatric nail disorders represent a limited component of a general pediatric practice, it can be challenging for practitioners to establish expertise in the diagnosis and treatment of these conditions and to recognize when reassurance is appropriate or when referral to a specialist is necessary. This article summarizes the anatomy of the normal nail unit, as well as the evaluation and management of onychomycosis, melanonychia, trachyonychia, onychomadesis, and nail pitting.