Wide Local En Bloc Excision of Subungual Melanoma In Situ

Clinical and Histopathological Investigation of Pediatric Melanonychia: A Single-Center Retrospective Case Series

HYPOTHESIS

The natural history of pediatric melanonychia and the necessity of biopsy for ruling out melanoma are debated in the literature. We hypothesize that there is a low rate of malignant nail pathology among pediatric patients undergoing nail bed biopsy for melanonychia.

METHODS

We performed a retrospective chart review of 54 pediatric patients (age <18 years) at a single institution who presented with melanonychia and underwent nail bed biopsy from 2007 to 2022. Data points collected included patient demographics, medical history, physical exam findings, pathology reports, and clinical photos. Univariate and multivariate analyses were performed to assess for risk factors associated with high-risk pathology findings.

RESULTS

The average age of melanonychia onset was 5.5 years (SD 4.4). The average age of first biopsy was 7.8 years (SD 4.3). On physical exam, 27 patients had at least four features concerning for melanoma (asymmetry, border irregularity, color heterogeneity, diameter > 1/3 of nail, evolving color, evolving diameter, Hutchinson's sign). The most common pathology diagnoses were melanocytic nevus (35%), atypical intraepidermal melanocytic proliferation (AIMP) with benign features (24%), subungual lentigo (22%), and AIMP with concerning features (17%). There were no cases of melanoma in situ or invasive malignant melanoma. On multivariate regression, the only significant risk factor associated with more concerning pathology (AIMP with concerning features) was the calendar year in which biopsy was performed (coefficient = -0.34, P = 0.016). There was no association between physical exam features and high-risk pathology. Twelve patients had surgical re-excision of the lesion, 6 of which were due to incomplete excision of AIMP with concerning features and 6 of which were due to recurrence.

CONCLUSIONS

Our case series did not find any cases of melanoma in situ or malignant melanoma arising from pediatric melanonychia. Atypical intraepidermal melanocytic proliferation with concerning features was associated only with the year in which the biopsy was performed, which may reflect the improved understanding of pediatric melanonychia as often benign despite concerning features on pathology. The decision to perform a nail matrix biopsy in pediatric melanonychia should be based on a collaborative discussion between the patient's parents, dermatologist, and plastic surgeon.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A 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.

Local Recurrence of Melanoma Is Higher After Wide Local Excision Versus Mohs Micrographic Surgery or Staged Excision: A Systematic Review and Meta-analysis

BACKGROUND

Complete removal of melanoma is a primary goal of excision, and local recurrence is one measure to evaluate the efficacy of surgical technique.

OBJECTIVE

To compare published local recurrence rates for melanoma treated with Mohs micrographic surgery (MMS) or staged excision versus wide local excision (WLE).

METHODS AND MATERIALS

Search of 6 databases identified comparative and noncomparative studies that reported local recurrence rates after MMS, staged excision, or WLE for melanoma. Random-effects meta-analysis was used to estimate odds ratios and 95% confidence interval (CI) from comparative studies and event rates from noncomparative studies.

RESULTS

Of the 71 studies included (16,575 patients), 12 were comparative studies (2,683 patients) and 56 were noncomparative studies (13,698 patients). Comparative studies showed increased recurrence after WLE compared with MMS or staged excision (odds ratio [OR], 2.5; 95% CI, 1.4-4.6) and compared with MMS alone (OR, 3.3; 95% CI, 1.8-5.9). Pooled data from comparative and noncomparative studies showed a local recurrence rate of 7% after WLE (95% CI, 5%-11%), 3% after staged excision (95% CI, 2%-4%), and less than 1% after MMS (95% CI, 0%-1%). Statistical heterogeneity was moderate to high.

CONCLUSION

Local recurrence of melanoma is significantly lower after MMS (<1%) and staged excision (3%) compared with WLE (7%).

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.

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.

Childhood longitudinal melanonychia: case series from Poland

Introduction

Longitudinal melanonychia (LM) is characterized by a tan, brown or black longitudinal streak within nail plate caused by the presence of melanin. LM is relatively common in dark-skinned population, infrequent in Caucasian population, and rare in children.

Aim

We report epidemiological, clinicopathological and dermoscopic analysis of 8 cases of childhood LM from Poland, which is the largest series in the Central and Eastern European population.

Material and methods

Three hundred and forty-eight patients presenting with various nail pigmentation (in 2010-2016) were analysed. 72 cases of LM have been identified, including 8 cases of childhood LM (< 16 years of age), which were included in further analysis.

Results

Seven patients were boys and one girl, with mean age of 9 years (range: 6-13). More than a half (n = 5) presented skin phototype II. The most common location of melanonychia was the first left fingernail. Dermoscopy revealed heterogeneity of longitudinal lines colour in 5 cases. The irregularity of longitudinal line thickness in 5 cases and irregularity of parallelism in 5 cases was observed. Histopathological evaluation was performed in 4 patients, in 3 cases it revealed the presence of nail matrix nevus, in one case the presence of melanocytic proliferation of the lentiginous pattern along the dermoepidermal junction.

Conclusions

Despite the fact that melanoma was not recognised in any case, such a possibility should always be considered as the cause of LM, even in the paediatric population. Dermoscopy seems to be useful in patient follow-up and management.