Onychomatricoma has channel-like structures on in vivo reflectance confocal microscopy

Advances in image-based diagnosis of nail disorders

This paper provides a comprehensive overview of image-based techniques, particularly focusing on their applications and advancements in the context of nail disorders. Nowadays, high-resolution digital cameras and dermoscopes enable dermatologists to capture detailed images of nail abnormalities, facilitating early diagnosis and meticulous tracking of disease progression. Onychoscopy is now a routine technique with well-known criteria for the diagnosis, but recent developments allow us to visualize certain diseases better. Imaging modalities like high-frequency ultrasound, magnetic resonance imaging, optical coherence tomography and confocal microscopy are being increasingly adopted for their superior diagnostic capabilities. These techniques are described in their technology, scanning protocols, normal findings, advantages and limitations. Moreover, the integration of technology in patient education has fostered a more informed patient population, capable of actively participating in their disease monitoring and treatment regimens. Proper training, validation, regulation and ethical considerations are, however, essential when integrating technology into healthcare practices. Imaging technologies that present the potential to add critical anatomical information to clinical diagnoses within reasonable costs and are available worldwide are the ones that will probably be used the most.

Molecular characterization of onychomatricoma: Spatial profiling reveals the role of onychofibroblasts in its pathogenesis

Onychomatricoma (OM) is a rare nail unit tumour with a characteristic presentation of finger-like projections arising from the nail matrix. Due to the lack of transcriptome information, the mechanisms underlying its development are largely unknown. To characterize molecular features involved in the disease pathogenesis, we used digital spatial profiling (DSP) in 2 cases of OM and normal control nail units. Based on the histological evaluation, we selectively profiled 69 regions of interest covering epithelial and stromal compartments of each tissue section. Dermoscopic and histopathologic findings were reviewed in 6 cases. Single-cell RNA sequencing of nail units and DSP were combined to define cell type contributions of OM. We identified 173 genes upregulated in stromal compartments of OM compared to onychodermis, specialized nail mesenchyme. Gene ontology analysis of the upregulated genes suggested the role of Wnt pathway activation in OM pathogenesis. We also found PLA2G2A, a known modulator of Wnt signalling, is strongly and specifically expressed in the OM stroma. The potential role of Wnt pathway was further supported by strong nuclear localization of β-catenin in OM. Compared to the nail matrix epithelium, only a few genes were increased in OM epithelium. Deconvolution of nail unit cell types showed that onychofibroblasts are the dominant cell type in OM stroma. Altogether, integrated spatial and single-cell multi-omics concluded that OM is a tumour that derives a significant proportion of its origin from onychofibroblasts and is associated with upregulation of Wnt signals, which play a key role in the disease pathogenesis.

Magnetic Resonance Imaging in the Diagnosis of Onychomatricoma: A Case Report

Onychomatricoma (OM) is a rare benign tumour of the nail matrix characterized by specific clinical and histologic features. The main clinical signs are thickening of the nail plate, xanthonychia, overcurvature of the nail plate, and multiple splinter haemorrhages. The diagnosis is based on clinical, radiological and histopathological findings. Histologically, the tumour is characterized by filiform epithelial projections. The objective of this study is to present the first reported Tunisian case of OM, focusing on the contribution of magnetic resonance imaging to the diagnosis of OM. A review on the subject is also presented.

Onychomatricoma: A Rare Nail Tumor with an Unusual Clinical Presentation

First described in 1992, onychomatricoma is a rare, benign, fibroepithelial tumor of the nail matrix with few reported cases in the literature. The tumor predominately affects the fingers of Caucasian women during the 5th decade of life and is typically slow growing and painless. The authors present a unique clinical presentation of a giant onychomatricoma in a darker-skinned 60-year-old South Asian individual who presented with a large dome-shaped nail that was smooth, shiny, and green.

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.

Tips to diagnose uncommon nail disorders

This article reviews 6 nail disorders that, although easy to diagnose, are misdiagnosed frequently by dermatologists and general practitioners. Diagnostic clues are emphasized to familiarize readers with features that indicate the correct diagnosis. We focus on two common tumors (onychomatricoma and onychopapilloma), two rare genetic conditions that can be diagnosed owing to nail changes (Darier disease and nail patella syndrome), and two uncommon acquired disorders (the yellow nail syndrome and lichen striatus).