Squamous Cell Carcinoma of the Nail Unit: Review of the Literature

Squamous cell carcinoma of the nail in patients with Fitzpatrick phototypes IV-VI: a systematic review

Squamous cell carcinoma of the nail unit (nSCC) is a rare malignant tumor of the hand and nail. Although skin cancer rarely affects individuals with phototypes IV-VI, its occurrence in these groups is often associated with greater morbidity and mortality. This study aims to characterize the clinical symptoms, presentations, and treatments of nSCC in patients with darker skin types. A systematic review of PubMed and Embase was performed in May 2023 for all peer-reviewed, English-language nSCC studies involving individuals with Fitzpatrick types IV-VI. Most tumors were located on the fingernails (84%), with the right third finger being the most frequently affected (31%). The nail bed (67%) exhibited a higher prevalence than the lateral/proximal nail folds (33%). The duration of symptoms before diagnosis ranged from 1 month to 7 years. nSCC was most commonly treated with Mohs surgery (38%), followed by amputation (35%). Our study was limited to case reports because of a lack of large nSCC studies that provide information on race or images of each patient. These tumors are generally slow-growing yet often misdiagnosed, leading to delays in presentation and diagnosis. Increased awareness about nSCC in phototype IV-VI individuals will reduce misdiagnoses, unnecessary treatment, and recurrences.

Evaluation of the Knowledge of Primary Care Physicians About Important Nail Diseases Before and After a Short Online Training

INTRODUCTION

Nail diseases are often diagnosed late with a potential prognostic and functional impact. This could be partly due to knowledge gaps among primary care physicians (PCPs).

OBJECTIVES

To evaluate the knowledge about diagnosis and management of ten common/important nail conditions in a population of French PCPs and its improvement after a 31-minute online training session.

METHODS

We submitted 10 pre-test and post-test clinical cases and an educative online course on the diagnosis and the management of nail diseases to 138 volunteer PCPs; 73 completed the whole training path.

RESULTS

Compared to pre-test, more PCPs in the post-test required an urgent second opinion to dermatologist for pigmented melanoma (100% versus 80.3%; P <0.05) and use of inappropriate/dangerous systemic treatment for trauma-induced nail changes was reduced after the training program (0% versus 6.8%; P <0.05). A lack of knowledge remained after training for amelanotic melanoma with an increase of mycological/bacteriological tests (9.6% versus 0%; P <0.05).

CONCLUSIONS

Management of nail diseases by our panel of PCPs was suboptimal and was improved after a short online training.

MRI of squamous cell carcinoma of the nail apparatus: report of 6 cases

Malignant tumors of the nail apparatus are rare and dominated by squamous cell carcinomas (SCC). Routinely, their pre-therapy imaging is limited to radiography. Our purpose is to determine the MRI characteristics in the locoregional assessment of SCC of the nail apparatus through a series of 6 consecutive cases explored by MRI and operated, carried out over a period of 12 years. IRB approval was obtained. Two in situ and 4 invasive squamous cell carcinomas were found, sex ratio was 0.5, and the age was 55 ± 10 years (mean ± SD). Most tumors showed specific signal behavior different from that of the epidermis and dermis with high signal on T2wi (5/6) and complete or partial enhancement (6/6). The mean thickness was 3.4 mm. The deep margin of the tumor with the dermis was always well defined for Bowen's disease (2/2) and blurred for invasive SCC. Localization involved the nail bed epithelium in all cases. Changes of the nail plate were detectable. Extension to lateral and posterior folds, hyponychium, cul-de-sac matrix, deep dermis, and bone was determined. MRI could be proposed as preoperative imaging of squamous cell carcinoma for locoregional assessment and guide biopsy.

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.

Squamous Cell Carcinoma of the Nail Unit After Trauma: A Case Report

Squamous cell carcinoma of the nail unit (SCCNU) is a relatively uncommon tumor with a low rate of metastasis. SCCNU presents with nonspecific symptoms and signs, it is frequently misdiagnosed by dermatologists or surgeons. We report a patient with right-hand ring subungual squamous cell carcinoma who received inappropriate treatment due to a long-term misdiagnosis following trauma. This patient had been treated with acitretin combined with cefaclor, and a certain curative effect was seen, but finally, wide local excision was performed.

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.

Treatment Options and Outcomes for Squamous Cell Carcinoma of the Nail Unit: A Systematic Review

BACKGROUND

Nail squamous cell carcinoma (nSCC) is the most common nail unit malignancy. However, no studies to date have evaluated treatment options for nSCC based on recurrence data while controlling for invasion.

OBJECTIVE

To identify temporal trends in nSCC treatment modalities and compare treatment outcomes based on invasion.

METHODS AND MATERIALS

The authors performed a systematic review of articles published on PubMed, MEDLINE, and Scopus from inception to April 2020 reporting treatment of nSCC. The primary outcome was disease recurrence.

RESULTS

Reports of nSCC treatments have increased in the past decade. Mohs micrographic surgery (MMS) is the most common treatment reported overall. The lowest recurrence rates for in situ nSCC were seen with wide surgical excision (WSE) and MMS. For invasive disease, the recurrence rates were lowest with amputation, MMS, and WSE.

CONCLUSION

Complete surgical excision of nSCC with either WSE or MMS is associated with lower recurrence rates than limited excision and nonsurgical therapies, regardless of degree of invasion. The prognostic significance of in situ versus invasive disease remains unclear. Confirmation of complete excision may improve outcomes. Digital amputation is indicated for nSCC with bone invasion. Prospective studies and randomized controlled trials are needed to directly compare surgical modalities for nSCC.

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.

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.

Polydactylous Squamous Cell Carcinoma of the Nail Unit: A Structured Review of the Literature

Squamous cell carcinoma of the nail unit (SCCNU) is a rare neoplastic condition that involves multiple digits (polydactylous SCCNU) in only 3.9% of cases. Here, we report a case of polydactylous SCCNU and perform a comprehensive review of MEDLINE and Embase to collate 44 cases of polydactylous SCCNU reported to date. Polydactylous patients were younger on average (48 to 61-63 years) and had a longer diagnostic delay (44 vs 35.1 months) compared with reported monodactylous cases. Human papillomavirus (HPV) positivity was observed in 49% of cases, and the most common serotypes noted were 16 (25.8%), 73 (16.1%), 58 (9.7%), 18 (6.5%), and 33 (6.5%). Twenty percent of the cases were in immunosuppressed individuals who had a statistically significant lower age at diagnosis (39.33 years vs 51.12 years; P = .01) and diagnostic delay (2.50 months vs 132.46 months, P = .04). Patients with HPV positivity had a lower age at diagnosis (43.74 years vs 53.29 years, P = .04). Environmental exposures noted to be associated with polydactylous disease included X-rays, paint/solvents, soluble oils, and stagnant water. This comprehensive literature review serves to characterize polydactylous SCCNU and distinguish the differences in its characteristics to improve diagnosis and clinical recognition.

Subungual Invasive Squamous Cell Carcinoma with Doubtful Underlying Bone Invasion: A Treatment Proposal

Introduction

Subungual squamous cell carcinoma (sSCC) is the most frequent malignant tumor of the nail unit. When suspecting sSCC, accurate diagnosis is supported by nail biopsy. Depth of invasion and histopathologic signs of human papillomavirus (HPV) infection are related to an unfavorable prognosis. In this case, it is necessary to rule out bone invasion by radiography or MRI, and in case of doubt, amputation is indicated.

Case Presentation

We present 2 cases of sSCC with a confirmatory biopsy of sSCC with HPV and invasion; in both cases, MRI was difficult to distinguish between bone invasion and bone marrow inflammation. Before amputating the distal phalanx, we decided to perform a bone biopsy during the excisional surgery. Neither case required amputation.

Conclusion

We propose that when an invasive sSCC is present and an MRI is doubtful of bone invasion, before amputating, a bone biopsy should be performed.

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.