Prevalence of subungual melanoma in patients with cutaneous malignant melanoma: A systematic review and meta-analysis.

BACKGROUND: Subungual melanoma (SUM) is a rare type of cutaneous malignant melanoma (CMM) associated with poor prognosis, while data regarding its prevalence are scarce. OBJECTIVES: We sought to provide a comprehensive systematic review and meta-analysis of the prevalence rates of SUM among all types of CMM, considering certain demographic and clinical characteristics. METHODS: The MEDLINE electronic database was searched systematically to identify eligible studies providing prevalence rate estimates of SUM in patients with CMM. Included studies were further analysed to estimate the relative prevalences of SUM according to study design, study years, geographical region and sex distribution. RESULTS: Twenty-eight studies met the inclusion criteria. The overall SUM prevalence was 1.9% (95% CI [1.5%-2.3%]). The prevalence of SUM did not differ significantly between population- and hospital-based studies and remained stable over time. However, it was found to be significantly higher in Asians compared to patients of other geographical regions as well as in studies with more men than women compared to those with female preponderance (p < 0.001). CONCLUSIONS: In all, the overall SUM prevalence among all subtypes of CMM was estimated at 1.9%, without significant changes over time, and was found to exhibit significant variability between subgroups of different geographical regions.

Transillumination: A Diagnostic Tool to Assess Subungual Glomus Tumors.

Diagnosis of subungual glomus tumors is mainly based on clinical symptoms, including paroxysmal pain, tenderness, and cold intolerance. Dermoscopy, ultrasonography, and MRI constitute further diagnostic tools, commonly performed to demarcate the tumor before surgery. Herein, we present 2 cases of subungual glomus tumors, which could be diagnosed after fingertip transillumination, highlighting that this technique can serve as an easy, noninvasive, and cost-effective adjuvant diagnostic tool, to facilitate the clinical diagnosis of subungual glomus tumors as well as their localization during preoperative assessment.

Giant Onychomatricoma of the Great Toenail: Case Report and Review Focusing on Less Common Variants.

Onychomatricoma is a rare benign fibroepithelial filamentous tumor originating from the nail matrix. It typically presents with the clinical tetrad of xanthonychia, pachyonychia, proximal splinter hemorrhages and increased transverse overcurvature of the nail plate. The giant variant can easily confuse the clinician due to its extensive nail dystrophy that can mask the characteristic features of this tumor. Benign (fibrokeratoma, ungual fibroma, onycholytic matricoma) and malignant entities (Bowen's disease, squamous cell carcinoma, onycholytic carcinoma) are mimics of the disease. Nail surgery can facilitate the diagnosis, which should always be confirmed by histology, as rare variants do exist.