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.

The appropriate use of therapeutic moisturizers could reduce the need for more aggressive treatment in the management of atopic dermatitis (AD). We conducted a randomized, side-by-side, single-blinded, comparative study in 41 mild to moderate AD patients to compare a moisturizer and topical tacrolimus for restoring skin barrier function and managing AD. A moisturizer was applied twice daily for 4 weeks to one side of the flexural areas (moisturizer group). Topical tacrolimus was applied on the other side of the tested area (tacrolimus group). Biophysical skin parameters were measured at baseline, week 2, and week 4. Clinical qualitative assessments were also conducted. Analysis of the trend from baseline to week 4 revealed that the hydration level was significantly increased in both groups ( p < 0.01 , respectively). No biophysical parameters were significantly different between the two groups. Differences in the modified Eczema Area and Severity Index scores between the baseline and week 4 were significantly higher in the tacrolimus group than those in the moisturizer group ( p = 0.002 ). In the Investigator’s Global Assessment, a significantly larger proportion of patients in the tacrolimus group showed clinical improvement than that in the moisturizer group at week 4 ( p = 0.027 ). Although topical tacrolimus was superior to the moisturizer in preventing the clinical exacerbation of AD, the moisturizer was not inferior to topical tacrolimus in restoring skin barrier function. Therefore, moisturizer is considered to play an essential role in maintenance therapy for AD. Physicians need to emphasize the benefits of moisturizers when educating their patients.

BackgroundCutaneous metastasis (CM) refers to the spread of malignancy to the skin. CM is perceived as an advanced stage. It might be the first sign of a primary cancer or an indicator of recurrence.ObjectivesTo identify primary cancers associated with CMs and perform a survival analysis according to advanced stage of cutaneous metastasis at a single tertiary center in Korea.MethodsA total of 219 patients from Samsung Medical Center from January 2009 to April 2020 were retrospectively analyzed to identify cases with biopsy‐proven CMs. According to advanced stage of metastasis, patients were divided into three stages, CM only (CMO), CM with lymph node metastasis (CM/LM), and CM with distant metastasis (CM/DM), to analyze clinical characteristics and survival rate.ResultsThe most common CM from primary cancer was breast cancer, followed by lung cancer, stomach cancer, colorectal cancer, and others. When all primary cancers were included, the median survival period was 4.82 years for the CMO stage, 2.15 years for the CM/LM stage, and 0.80 years for the CM/DM stage, with a tendency to deteriorate with advancing stage. At 1‐year and 3‐year after occurrence of CM, the CM/DM stage showed a significantly poorer survival rate than the other two stages.ConclusionsThis study showed a median survival period of 22 months for CM patients overall. Breast cancer has greater accessibility to the skin than other cancers. Therefore, breast cancer can metastasize to the skin without involving lymph nodes or other sites.