Mohs micrographic surgery for nail unit tumours: an update and a critical review of the literature

Slow Mohs micrographic surgery for nail apparatus melanoma in situ

BACKGROUND

Nail apparatus melanoma is a malignant tumor with a high incidence in Chinese melanoma patients. Slow Mohs micrographic surgery is an emerging technique for treating nail apparatus melanoma in situ (NAMIS).

OBJECTIVE

This study evaluated the efficacy and safety of slow Mohs micrographic surgery for treating NAMIS.

METHODS

Patients were enrolled in this retrospective study and treated in a single center from October 1, 2016, to June 30, 2022. Each patient underwent standard slow Mohs micrographic surgery, and follow-up was regularly conducted at clinics.

RESULTS

Ten patients were enrolled in the study. Two patients underwent one Mohs stage, seven underwent two Mohs stages, and one underwent seven Mohs stages. The resection margin ranged from 5 to 25 mm. No severe complications were reported in the treatment, and recurrence of NAMIS was not observed during the follow-up period.

CONCLUSION

Slow Mohs micrographic surgery is a valuable surgical method to treat NAMIS that preserves digit function and can be well tolerated by patients.

Diagnosis and surgical treatment of benign nail unit tumors

Little is known about benign non-melanocytic nail tumors, probably due to their low pathogenicity. They are commonly misdiagnosed as inflammatory or infective diseases. They have various features, depending on the type of tumor and its location in the nail apparatus. The typical sign of a tumor is the presence of a mass and/or secondary nail changes from damaged nail structures. In particular, if a single digit is affected by a dystrophic sign or a symptom is reported without any explanation, the presence of a tumor should always be ruled out. Dermatoscopy helps to enhance visualization of the condition and in many cases supports the diagnosis. It may also assist in identifying the right place to biopsy, but it never replaces surgery. Most common non-melanocytic nail tumors are analyzed in this paper, including glomus tumor, exostosis, myxoid pseudocyst, acquired fibrokeratoma, onychopapilloma, onychomatricoma, superficial acral fibromyxoma and subungual keratoacanthoma. The aim of our study is to review the main clinical and dermatoscopic characteristics of the most common benign non-melanocytic nail tumors, to correlate them with the histopathology and to advise practitioners of the best surgical management.

Squamous Cell Carcinoma in Situ of the Nail Unit: Current Evidence and Recommendations for Patient Centered Treatment

Squamous cell carcinoma in situ of the hand and nail is an infrequent tumor but represents the majority of hand and nail malignancies. While the conventional treatments of invasive nail unit squamous cell carcinoma include Mohs micrographic surgery, wide local excision, or distal digit amputation, no standardized management paradigm for in situ disease exists and the necessity of surgical options is debated. This review aims to discuss the most commonly reported treatment methods and critically assess relevant management considerations in order to facilitate appropriate treatment decisions for nail unit SCCis across dermatologic practice settings. Assessment of the current literature reveals insufficient evidence to determine a standardized treatment for nail unit squamous cell carcinoma in situ. Rather, management is greatly impacted by multiple factors including the presence of subungual involvement, surgical candidacy, importance of curative treatment, and patient preferences regarding cosmesis and function versus cure. When cure is desired, Mohs micrographic surgery is the treatment of choice in most cases. In the setting of desired curative intent, but poor surgical candidacy, radiotherapy may be effective and provide a reasonable chance of functional and cosmetic preservation. Other methods including photodynamic therapy, electrodesiccation and curettage, cryotherapy, and intralesional chemotherapeutics may be appropriate in specific circumstances, but are generally limited by lack of evidence or impracticalities. Lastly, observation with palliation may be appropriate when considering exceedingly rare disease-related mortality.

Mutational landscape in squamous cell carcinoma of the nail unit

Squamous cell carcinoma (SCC) is the most common malignancy of the nail unit. Pathogenetic mechanisms are yet to be determined, and a deeper molecular characterization of this disease is still necessary. The aim was to obtain a molecular characterization of NU SCC samples using an NGS approach to identify the genetic drivers involved in this tumor. The presence of HPV infection was also assessed. Furthermore, the mutational status was correlated with specific clinical-pathological features for a better insight into the carcinogenesis of this uncommon tumor. We analysed twenty paraffin-embedded nail unit SCC samples from patients diagnosed with primary SCC of the nail unit by next genome sequencing. In the 20 tested samples, the neoplastic cells enrichment ranged from 10% to 50% (mean value: 25.7%). In 14/20 cases (70.0%), at least one mutation was detected; whereas in the other six cases (30.0%), no alterations were observed ('wild-type/WT cases'). Overall, a total of 23 mutations were identified in the 20 specimens. TP53 was the most mutated gene (6/20 cases, 30.0%), while cKit, GNAS, EGFR, DICER1 and CTNNB1 were observed in one sample each (5.0%). No clinical-pathological parameters (age, sex, depth of invasion-DOI, histological subtype, grading and HPV) were significantly associated with the mutational status. The nail unit SCC mutational landscape appeared to be heterogeneous, favouring the hypothesis of a complex pathogenesis and an interaction of multiple elements, including HPV infections. This wealth of information undoubtedly improves our understanding of SCC biology.

Nail Cancer: Review of the Two Main Types of an Underestimated Disease

Neoplastic lesions (benign or malignant) in the nail region are rare when compared to lesions in the rest of the skin. Despite advances in diagnostic modalities, their diagnosis is frequently delayed or overlooked for days, months, or even years when they are misrecognized or when their approach is not appropriate. Undoubtedly, malignant tumors are the most important lesions since an inopportune diagnosis or treatment can drastically change the patient's prognosis.

A review of all the scientific evidence on the two main malignant neoplasms of the nail apparatus (melanoma and squamous cell carcinoma) was carried out using the PubMed search engine from 2003 to 2022, in order to expose the appropriate diagnostic approach and treatment of these nail lesions to avoid delays that obscure the prognosis of patients. This review does not include reconstruction modalities after lesion resection, but the emphasis is placed on the great functional impact they produce. Surgical treatment in the early stages is the most important when talking about prognosis and emphasizing it; systemic oncological management of advanced stages is not so deep.

Squamous Cell Carcinoma of the Nail, an Underdiagnosed and Underestimated Entity: A Series of Two Cases

The nail apparatus is a complex area with great functional and cosmetic importance. The appearance of tumors is rare, frequently misdiagnosed with delaying the diagnosis. A series of cases is presented, where squamous cell carcinoma of nail apparatus underwent resection and reconstructive surgery in a relatively short time from their diagnosis, with a good oncological, functional, and cosmetic result.

Grafting and Other Reconstructive Options for Nail Deformities: Indications, Techniques, and Outcomes

This article reviews the nomenclature, anatomic components, and physiologic growth involving the perionychium. Fingertip and nailbed injuries are commonly encountered problems in hand surgery. This article focuses primarily on dealing with chronic nailbed deformities following traumatic injury such as nonadherence, split nails, avulsion loss, and hook nails. Nail deformities secondary to pincer nail, mass effect, and pigmented lesions are reviewed as well. The underlying pathology and treatment options are examined for each deformity. The senior author highlights technical pearls and surgical planning for his preferred methods of reconstruction.

Cutaneous and Mucosal Melanomas of Uncommon Sites: Where Do We Stand Now?

Melanomas arising at uncommon sites include a group of lesions related to unusual localizations in specific ethnic groups. The rarity of the disease often represents a limit to the participation of patients in specific trials. However, this peculiar genetic scenario has important therapeutic implications regarding new oncologic therapies. The aim of this article is to review the clinical features, somatic alterations and therapeutic options for melanomas of uncommon sites. They can be classified as cutaneous and mucosal lesions affecting the nail apparatus, palms/soles, oral mucosa, genital area and scalp. The prognosis may be worse compared to melanomas of other districts, and a prompt diagnosis may dramatically influence the outcome. Dermatologists and oncologists should therefore distinguish this melanoma subgroup in terms of surgical intervention and medical treatment. Due to the lack of mutations in genes usually found in cutaneous melanomas, the discovery of novel targets is required to develop new strategies and to change the prognosis of non-responders or wild-type patients.

It's time for Mohs: Micrographic surgery for the treatment of high-risk basal cell carcinomas of the head and neck regions

Basal cell carcinoma (BCC) is the most common variety of non-melanoma skin cancer and its incidence is increasing worldwide. The centrofacial sites (area H) are considered a high-risk factor for BCC local recurrence. Mohs micrographic surgery (MMS) is a technique that allows intraoperative microscopic control of the surgical margins and is a good treatment option when tissue conservation is required for esthetic or functional reasons or for high-risk lesions. The present study aimed to evaluate the recurrence rate of head and neck high-risk BCCs comparing MMS vs conventional surgical excision. Clinical data of patients diagnosed from September 2014 to March 2017, referring to the Dermatology Unit of the Policlinico Sant'Orsola-Malpighi, University of Bologna, were retrospectively evaluated (285 treated with MMS and 378 treated with traditional surgery). Of the 285 patients treated with MMS, 9 experienced a recurrence (3.1%). Of the 378 patients treated with traditional surgery, 53 relapsed (14%), 13 of whom presented residual tumor on the deep or lateral margins of the main surgical specimen. Our study confirms the trend reported in the literature that MMS represents the best treatment option for high-risk BCCs arising in the head and neck region or presenting as a recurrence (P < .00001). Many more MMS centers and more trained dermatologists are needed worldwide in order to deal with the increasing number of BCC diagnosed every year.

Oral and nail pigmentations: a useful parallelism for the clinician

Oral (OP) and nail (NP) pigmentations may occur simultaneously in physiological or pathological conditions, and may be a sign of underlying syndromic conditions that necessitate further investigation and treatment. Interestingly, the nail unit and oral cavity show a clinical parallelism that may help the clinician to conduct a correct examination and reach a prompt diagnosis. Both OP and NP can manifest clinically with focal or diffuse involvement and are due to external factors (exogenous pigmentation, drug-induced pigmentation) or endogenous factors (racial pigmentation, post-inflammatory pigmentation, nevi, genetic conditions and other disorders). The most concerning differential diagnosis is melanoma. Here we report the pathogenetic basis of OP and NP, together with the description of similar clinical features. To the best of our knowledge this is the first paper to summarize and describe the causes of pigmentation of both the oral cavity and the nail unit.

Subungual Tumors: An Algorithmic Approach

The presentation of benign and malignant subungual tumors often follows a final common pathway of nonspecific nail deformity; as such, delays in diagnosis are common. Therefore, it is imperative to have a high degree of suspicion for malignant lesions and an organized approach to subungual tumors. To that end, we present a diagnostic algorithm encompassing the most common benign and malignant subungual tumors, along with a summary of the presentation, imaging, and treatment of these lesions.