Tangential excision of pigmented nail matrix lesions responsible for longitudinal melanonychia: evaluation of the technique on a series of 30 patients

Onychomatricomas: A 41-Case Series to Assess Surgical Outcome

BACKGROUND

Onychomatricoma (OM) is a rare benign tumor of the nail matrix. Treatment is surgical, but data are currently limited.

OBJECTIVE

To review all cases of OM operated in their department and to assess the link between the location on the nail plate, the thickness and width of the lesion, and the postoperative outcomes.

MATERIALS AND METHODS

Records of 62 patients were retrieved from their department's database over a 25-year period (1998-2023).

RESULTS

Of the 62 patients, 41 were eligible. In total, 58% of OM occupied a width of a quarter of the nail plate, 51% had a plate thinner than 3 mm, and 51% were laterally located. Of the 41 patients included, 29 had a tangential excision and 12 underwent lateral longitudinal excision. Among the tangential excision group, 71% had normal nail regrowth. Onychomatricoma thicker than 3 mm and involving the total nail plate width had a sequelae in 60% of cases.

CONCLUSION

Tangential excision of onychomatricomas allows a normal nail regrowth in 71% of cases. The risk of sequelae increases for tumors thicker than 3 mm and involving the total nail plate width. Medial or lateral location seems to have no influence.

Managing longitudinal melanonychia

Longitudinal melanonychia (LM) is a pigmented band extending from the matrix to the distal edge of a nail. It is caused by increased production of melanin within the matrix, and integration into the nail plate. The origin of this production is usually benign, due to activation, hyperplasia or proliferation of melanocytes normally present in the matrix. In some cases, however, LM is the manifestation of a subungual melanoma, the diagnosis of which must be made early. Biographical, clinical and dermoscopic criteria make it possible to suspect melanoma and decide whether to perform biopsy. None of these criteria, however, are specific and definitive diagnosis requires pathologic examination of a matrix biopsy. The biopsy technique should enable reliable histological study while limiting the risk of secondary nail dystrophy. Initial resection should ideally involve the entire lesion. Complete elevation of the nail plate enables the lesion to be precisely located. Lesions up to 3 mm can be removed by longitudinal resection biopsies without significant sequelae. In more extensive lesions, incision or tangential ("shave") biopsy can be performed without impairing prognosis. In clinical presentations strongly suggestive of melanoma, immediate complete resection of the entire nail unit may be proposed.

Update on nail unit histopathology

Histopathologic evaluation of the nail unit is an essential component in the diagnosis of nail unit disorders. This review highlights recent updates in nail unit histopathology and discusses literature covering a wide range of nail disorders including melanoma/melanocytic lesions, squamous cell carcinoma, onychomatricoma, onychopapilloma, onychomycosis, lichen planus, and other inflammatory conditions. Herein we also discuss recent literature on nail clipping histopathology, a useful and noninvasive diagnostic tool that continues to grow in popularity and importance to both dermatologists and dermatopathologists.

Management of Nail Unit Melanoma

Nail unit melanoma is an uncommon form of melanoma with worse prognosis compared with nonacral cutaneous melanoma. Nail unit melanoma is often diagnosed at a late stage. Clinical and dermoscopic features may suggest a diagnosis of nail unit melanoma, but confirmation requires histologic analysis. Like the clinical diagnosis, histopathologic diagnosis of nail unit melanoma is also difficult. The surgical management of nail unit melanoma has evolved from aggressive amputations to digit-sparing approaches. This article reviews the clinical presentation, diagnosis, and surgical treatment of nail unit melanoma to promote early diagnosis and rational surgery.

Nail Surgery: Six Essential Techniques

Successful nail surgery requires an understanding of specific disease processes, the anatomy of the nail unit, and fluency with only a few key techniques. This article focuses on 6 high-yield procedures, facility with which will allow the clinician to approach most of the clinical scenarios requiring surgical intervention. These encompass surgical approaches to inflammatory nail diseases, melanonychia, erythronychia, and nail melanoma in situ.

Nail Biopsy: A User's Manual

Nail biopsy is a procedure not routinely resorted to; but when indicated, it is often the only clue left for diagnosis. At such times, it pays to be conversant with it. It is an investigation that not only provides etiologic, diagnostic, and prognostic information but also aids in understanding the pathogenesis of nail diseases. It can be of therapeutic value, especially with respect to nail tumors. This article compiles the procedural techniques for nail biopsy of various types and attempts to summarize the evidence available in the literature. The objective of nail biopsy is to clinch a precise diagnosis of nail pathology with a simple and safe surgical procedure, avoiding pain or permanent nail damage. Patient selection is of utmost importance, wherein, the patient does not have typical skin lesions, yields inadequate information on routine nail investigations, and has no peripheral vascular compromise. The patient needs to be explained about the risks associated, the expected functional handicap, the time required for regrowth, a possibility of permanent nail dystrophy, and a possibility of not achieving a diagnosis even after the biopsy. Techniques and types of various nail biopsies are being discussed in this article. The specimen could be collected as an excision biopsy, punch biopsy, shave biopsy, or longitudinal biopsy. The trick lies in choosing the appropriate area for biopsy. Various biopsy types discussed in this article include nail plate biopsy (easiest and least scarring); nail bed biopsy (elliptical excision or punch); nail matrix biopsy (elliptical excision, punch excision (≤3 mm) or tangential/shave excision); and nail fold biopsy. Complications reported along with means to minimize them are also discussed.

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.

Spontaneous Regression of a Nail Matrix Melanocytic Nevus in a Child

A 14-year-old Hispanic boy presented with a 0.25-mm wide, sharply demarcated, dark brown band of longitudinal melanonychia of the left thumbnail. A clinical diagnosis of nail matrix nevus was made and the boy was scheduled for follow-up. The band showed proximal fading after 6 months and had completely faded after 11 months, with the proximal nail fold showing small dark brown dots on dermoscopy. We documented the spontaneous regression of melanonychia over 11 months.

Dermatologic Manifestations of the Lower Extremity: Nail Surgery

Nail surgery is a fundamental component of podiatric surgery. Nail disorders are common and may cause significant morbidity and occasionally mortality. Diagnosis of inflammatory and infectious conditions, and of benign or malignant tumors, often requires a biopsy of the nail unit. Excisional surgery may also be curative for certain tumors. This article reviews key elements of nail anatomy, surgical preparation, local anesthesia, and methods to achieve and maintain a bloodless field. A familiarity with these concepts should allow clinicians to develop a surgical plan and approach when patients present with a nail disorder requiring biopsy or surgical treatment.

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.