No abstract available.
Herpes Simplex ; Simplexvirus ; Skin Diseases

Intralymphatic histiocytosis (ILH) is a rare cutaneous condition with uncertain pathogenesis. It is characterized by dilated lymphatic vessels that contain histiocytes within their lumina. Although the etiology of ILH remains unknown, it has been associated with various inflammatory and neoplastic diseases, such as rheumatoid arthritis (RA), reaction to metal joint implants and Merkel cell carcinoma, breast cancer and colon cancer. An 83-year-old female presented with an erythematous patch on the left forearm that had appeared six months previous. She had suffered from osteoarthritis (OA) and the cutaneous lesion was located in the vicinity of the affected joint. Skin biopsy from the lesion showed dilated dermal vessels and some ectatic vessels that contained many mononuclear histiocytes. Based on the clinical and histopathological findings, we diagnosed her with ILH with OA. Two sessions of intralesional triamcinolone acetonide injection (5 mg/ml) were administered to treat the skin lesion, which gradually improved over a period of a few months. We here report a rare case of ILH associated with degenerative OA.

Background: The prevalence of psoriasis differs by population, and it appears to be more common among Europeans than in East Asians. Recent genome-wide association studies (GWAS) have identified alleles that increase the risk of psoriasis, and these alleles may present different frequencies in different geographic regions. Objective: We aimed to gain insights into the causes of differences in disease frequencies according to populations and the factors affecting prevalence and pattern differences. Methods: We collected a total of 147 psoriasis-associated single-nucleotide polymorphisms (SNPs) from the GWAS catalog and compared the allele frequency differences in 27 populations using public population frequency in the 1000 Genomes Project phase 3 (n=2,504) and the Korean Reference Genome Database (n=1,722). Additionally, we calculated the composited genetic risk scores across the population groups. Results: There were distinct patterns of allele frequencies in different population groups.In many cases, East Asians exhibited allele frequencies opposite to that of Europeans. The genetic risk score was higher in Europeans (average: 0.487) and Americans (average: 0.492) than in East Asians (average: 0.471). The prevalence of psoriasis correlated with the average genetic risk score of the population. Conclusion We observed a difference in the allele frequencies of psoriasis-associated SNPs between the studied populations. This result suggests that the difference in the prevalence of psoriasis between population groups can be interpreted to some extent by the genotype.

Cytomegalovirus (CMV) infection is common among immunocompromised hosts; however, its cutaneous manifestation is considered rare in comparison to internal organ involvement. Clinical manifestations of cutaneous CMV infection generally include perioral or perianal ulcerations. On the other hand, autoimmune bullous dermatosis can have bullae and ulcerations similar to those caused by cutaneous CMV infection. Autoimmune bullous dermatosis requires treatment with immunosuppressive agents for relatively long periods, which may cause reduction of immunocompetence. Because of this iatrogenic immunosuppression, patients with autoimmune bullous dermatosis subsequently acquire increased risk for opportunistic infections. However, cases of bullous pemphigoid (BP) complicated by cutaneous CMV infection are rarely reported. Herein, we report the case of an 88-year-old male who had BP and subsequently recalcitrant perianal skin lesions, which were eventually diagnosed as cutaneous CMV infections.

Nivolumab is a fully-humanized IgG4 monoclonal antibody that competitively binds to the programmed cell death receptor-1 protein (an immune check-point molecule) present on activated T cells. Nivolumab is approved for the treatment of advanced melanoma, lung cancer, and renal cell carcinoma. It attenuates the inactivation of cytotoxic CD8+ T cells and, produces an antitumor effect; however it may be associated with immune-related adverse events, including the development of lichen planus (LP). A 72-year-old man presented with a 2-month history of multiple, polygonal, purplish papules on the dorsal aspect of both hands. He was diagnosed with large cell neuroendocrine carcinoma (LCNEC) of the lung 4 years earlier and was treated with nivolumab (3 mg/kg every 2 weeks) for 9 months. By the 14th course of nivolumab therapy, the patient developed multiple rashes on the dorsal aspect of both hands, and biopsy was consistent with findings of LP. We report a rare case of LP in a patient with lung cancer treated with nivolumab.
Aged ; Biopsy ; Carcinoma, Neuroendocrine ; Carcinoma, Renal Cell ; Cell Death ; Exanthema ; Hand ; Humans ; Immunoglobulin G ; Lichen Planus ; Lichens ; Lung Neoplasms ; Lung ; Melanoma ; T-Lymphocytes

Fibrofolliculoma is a benign perifollicular connective tissue tumor that usually occurs in the face. Most fibrofolliculoma present as multiple lesions and typically occur with trichodiscomas and acrochordons, constituting the Birt-Hogg-Dube syndrome. Solitary fibrofolliculoma is nonhereditary and unassociated with other cutaneous abnormalities. A 72-year-old man visited our clinic complaining of a solitary umbilicated nodule on the antitragus of the left ear. Skin biopsy from the lesion showed a central dilated follicular infundibulum with anastomosing bands of follicular epithelium extending into the fibrous stroma. The diagnosis of a solitary fibrofolliculoma was made based on the clinical and histopathological findings. No signs of lesion recurrence for 1 year after shave removal were noted. We report a rare case of solitary fibrofolliculoma that occurred on the antitragus of the ear.

Background: A direct potassium hydroxide (KOH) smear is used to diagnose onychomycosis despite its broad sensitivity range. For a more accurate diagnosis, histopathologic examination can be used and consistently show high sensitivity. Objective: We investigated the value of histopathologic examination of the nail plate as a diagnostic tool for onychomycosis. We proposed effective routine diagnostic staining to compare sensitivity between periodic acid-Schiff (PAS) and Gomori’s methenamine silver (GMS) staining. Methods: This retrospective study was conducted from January 1, 2019 to May 31, 2020, and included 97 patients who showed negative results on direct KOH smear but had clinical manifestations that implied onychomycosis. We performed nail plate biopsy and PAS or GMS staining to identify fungal hyphae missed in the direct KOH smear. Sensitivity comparison between PAS and GMS was performed in co-stained samples. Results: Among 97 patients with 102 cases, 55 cases (53.9%) of onychomycosis were confirmed by histopathologic examination. A total of 68 patients (70.1%) had a previous medical history of antifungal agents within previous six months. PAS and GMS staining were concurrently performed in 73 cases, and onychomycosis was confirmed in 41 cases. The sensitivity of PAS was 100% (41/41), while that of GMS was 87.8% (36/41); this difference was not significant. Conclusion This study suggests that histologic examination of the nail plate is an effective tool to diagnose onychomycosis and can be performed with a direct KOH smear. Two staining methods, PAS and GMS, are recommended for concurrent performance to enhance the identification of fungal hyphae.