Detection of early lesions of "ungual" malignant melanoma

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

BACKGROUND

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.

OBJECTIVE

To provide evidence of previously reported clinical factors indicative of NUM in patients with LM.

METHODS

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.

RESULTS

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.

CONCLUSION

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Subungual Melanoma

Subungual melanoma is a rare form of melanoma that presents a unique set of challenges largely based on the complex anatomy of the nail unit. Subungual melanoma often first appears with longitudinal melanonychia. Thus, practitioners must have a high clinical suspicion in any patient with longitudinal melanonychia and a low threshold for a biopsy. The "ABCDEF" guide can be a useful tool to aid in screening any lesion of the nail bed. The authors recommend that biopsies of the nail unit be performed by a surgeon with an in-depth understanding of the pathoanatomy of subungual melanoma.

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.

Early Detection of Subungual Melanoma In Situ: Proposal of ABCD Strategy in Clinical Practice Based on Case Series

Background

Prevalence of subungual melanoma (SUM) in Asian population is relatively high and early clinical detection improves both quality of life and survival.

Objective

We sought to establish screening strategy for SUM in situ.

Methods

We retrospectively reviewed medical records of 8 patients pathologically diagnosed as SUM in situ between January 2015 and September 2016.

Results

All patients in our study were adults and had solitary lesion. In all cases, longitudinal melanonychia as well as background pigmentation in entire nail plate was observed. Seven (87.5%) cases had periungual pigmentation. Clinical features of SUM in situ can be summarized according to new criteria categorized under initial letters of alphabet, namely nail ABCD of SUM in situ; “A” stands for adult age (age >18 years); “B” for brown bands in brown background; “C” for color in periungual skin; “D” for one digit. Our strategy was to suspect SUM in situ if solitary longitudinal melanonychia in adult was satisfying either “B” or “C” in ABCD. All cases were suspected as SUM in situ under nail ABCD rule, and histological examination confirmed diagnosis. Sensitivity and specificity of nail ABCD was 100% and 96.6%, respectively, regarding our previously published 18 SUM in situ and unpublished 28 nail matrix nevi cases as well as 8 SUM in situ presented here.

Conclusion

ABCD rule is simple and sensitive clinical strategy for early detection of SUM in situ.

Unusual molecular findings in Kindler syndrome

Kindler syndrome (KS) is a rare inherited skin disorder with blistering and poikiloderma as its main clinical features. It is caused by loss-of-function mutations in the C20orf42 (KIND1) gene which encodes kindlin-1, an actin cytoskeleton-focal contact-associated protein which is predominantly expressed in keratinocytes. We investigated the molecular basis of KS in a 16-year-old Indian boy who had additional clinical findings, including scleroatrophic changes of the hands and feet, pseudoainhum and early onset of squamous cell carcinoma on his foot. Immunostaining for kindlin-1 in the patient's skin was completely absent and sequencing of C20orf42 (KIND1) genomic DNA showed a homozygous splice-site mutation at the -6 position, IVS9-6T-->A. Amplification and sequencing of cDNA from the skin revealed aberrant splicing with either deletion of exon 10 or deletion of exons 9, 10 and 11, both of which involve loss of the pleckstrin homology domain of kindlin-1 that is thought to play a role in cytoskeletal attachment and integrin-mediated cell signalling. Pathogenic splice-site mutations at the -6 position are unusual and have rarely been reported for any genetic disorder. Collectively, these findings extend the spectrum of clinical and molecular abnormalities in this rare genodermatosis.

Dermoscopy of the nail bed and matrix to assess melanonychia striata

Melanonychia striata represents a diagnostic dilemma for dermatologists. The use of dermoscopy to assess the nail has advantages over clinical examination. However, when compared to skin lesions, it gives fewer details. We describe two cases of melanonychia striata submitted to dermoscopic examination of the nail bed and matrix. This is a new procedure that enables observing dermoscopic characteristics that are not visualized in the nail plate, thus, providing additional information.

Acral Lentiginous Melanoma In Situ: A Study of Nine Cases

An acral lentiginous melanoma (ALM) is the most common type of cutaneous melanoma in Asians. However, it is unusual to encounter a patient showing only the histologic features of an ALM in situ. Here we describe clinical and histologic features of nine cases of ALM in situ including immunohistochemical staining with anti-S100 protein and HMB-45. All the patients had a long clinical history. Clinically, the lesions were characterized by a longitudinal pigmented streak in the nail plates, black pigmentation on the proximal or lateral nail fold, and an irregular border and variegated pigmentation on the sole or thumb. Total resections of the lesions were performed in all patients. All lesions, in both biopsy and excisional specimens demonstrated more melanocytes generally located in the basal layer of the epidermis. There was no dermal invasion. No recurrence of the disease had occurred in any patient after a follow-up period of between 6 months to 12 years after surgery. These results suggest that ALM can evolve slowly over many years.

A subungual nevus in a Filipino child

A 2.5-year-old Filipino girl with a progressively growing, black, subungual lesion is described. A biopsy was performed because of the progressive increase in size of the lesion and its periungual involvement. Histologic examination revealed a junctional nevus. To our knowledge, this represents the first report of subungual nevus in a Filipino child. The need for histologic diagnosis prior to definitive surgery cannot be overemphasized.

Nail apparatus melanoma

Nail apparatus melanoma is a relatively rare variant of melanoma with a disproportionately high mortality when compared with melanoma elsewhere. The aetiology and natural history remain poorly understood. There is no clear epidemiological association with race, skin type or sun exposure. Universally accepted clinical and histological criteria for the diagnosis of early nail apparatus melanoma have not been defined. The two cardinal clinical signs are melanonychia striata and Hutchinson's sign. These are useful but not pathognomonic of melanoma. Diagnostic delay is frequent and patients commonly have advanced disease at the time of diagnosis. Surgical excision is advocated for treatment of stage I disease; however, the most appropriate re-excision margins, including the level of amputation where required, have not been determined. Early diagnosis and excision of the tumour is the only treatment known to increase survival. Adjuvant systemic chemotherapy, isolated limb perfusion, and routine elective lymph node dissection have been used, but no survival benefit has been demonstrated.

Early malignant melanoma manifested as longitudinal melanonychia: subungual melanoma may arise from suprabasal melanocytes

A 51-year-old woman developed longitudinal melanonychia of 3 months' duration on the right index fingernail. A biopsy specimen revealed that atypical melanocytes were distributed in the lower third of the matrix epithelium but were few in number at the basal layer. The involved nail matrix was resected because of continual growth of the lesion after the biopsy. It has been proven in normal nail matrices that melanocytes are distributed not only in the basal layer but also in the lower half of the epithelium. It is therefore understandable that malignant melanoma of the nail matrix can arise from melanocytes situated in the squamous epithelium above the basal layer. The present case is a good example in which malignant melanoma of the nail matrix may arise from the intraepithelial region where melanocytes normally reside.

Nail melanoma: a review of the literature with recommendations to improve patient management

In this review, the current state of knowledge concerning nail melanoma is summarized. The pathogenesis, histological findings, clinical presentation, treatment and prognosis of this rare form of cutaneous melanoma are discussed. Important clinical clues to the early diagnosis of nail melanoma are highlighted and recommendations to improve the management of patients are suggested.

Mohs micrographic surgery for the treatment of in situ nail apparatus melanoma: a case report

Nail apparatus melanoma (or subungual melanoma) is rare and accounts for only 1.4% of all cutaneous melanomas in the United Kingdom. We report the use of fixed-tissue Mohs micrographic surgery to treat a biopsy-proven Clark level I in situ nail apparatus melanoma, presenting with diffuse longitudinal melanonychia.

Nail matrix nevi: a clinical and histopathologic study of twenty-two patients

BACKGROUND

Because most dermatologists do not regularly perform biopsies of longitudinal melanonychia, even when the pigmentation presents as a single band, the true prevalence of nail matrix nevi is unknown.

OBJECTIVE

Our purpose was to determine the prevalence of nail matrix nevi in white patients with longitudinal melanonychia involving a single digit and to determine whether longitudinal melanonychia caused by a nail matrix nevus can be clinically distinguished from longitudinal melanonychia from other causes.

METHODS

From January 1989 to December 1994 we performed a nail biopsy on 100 of 128 consecutive white patients who had a single band of "idiopathic" longitudinal melanonychia.

RESULTS

A nail matrix nevus was detected in 22 patients. A junctional nevus was found in 19 specimens and a compound nevus in three specimens.

CONCLUSION

Nail matrix nevi in Caucasian patients are uncommon but not exceptional. The number of nevi presenting with longitudinal melanonychia exceeded that of melanoma. The diagnosis of nail matrix nevi is impossible clinically and always requires histopathologic study. The pathologic features of nail matrix nevi are similar to those of skin nevi except for their architectural pattern, which reflects the peculiar anatomy of the nail unit.