Involvement of the genus Corynebacterium in the pathogenesis of pigmented intratarsal keratinous cyst.

Intratarsal keratinous cyst (IKC) is a benign cystic lesion of the eyelid that retains keratin flakes. IKCs are usually yellow to white cystic lesions but rarely become brown or gray-blue, making clinical diagnosis difficult. The mechanisms by which dark brown pigments are generated in pigmented IKC are unclear. The authors report a case of pigmented IKC that had melanin pigments within the lining of the cyst wall and within the cyst. Focal infiltrates of lymphocytes were observed in the dermis, particularly beneath the cyst wall in areas with more melanocytes and intense melanin deposition. These pigmented parts faced bacterial colonies inside the cyst, which were identified to be Corynebacterium species in a bacterial flora analysis. The pathogenesis of pigmented IKC in relation to inflammation and bacterial flora is discussed.

Three cases of drug-induced hypersensitivity syndrome associated with mRNA-based coronavirus disease 2019 vaccines.

Drug-induced hypersensitivity syndrome (DiHS) is a severe drug eruption that can induce reactivation of herpesviruses such as human herpesvirus 6, resulting in symptom flare-up and organ damage. DiHS is known as drug reaction with eosinophilia and systemic symptoms (DRESS) in Europe. We report three cases of DiHS that could have been triggered by mRNA-based coronavirus disease 2019 (COVID-19) vaccines. In these three patients, symptoms of DiHS developed 2-6 days after the first dose of an mRNA-based COVID-19 vaccine. Although there have been no reports of DiHS/DRESS induced by mRNA-based COVID-19 vaccines in domestic and international journals despite the progress in vaccination worldwide, we speculate that mRNA-based COVID-19 vaccines might have triggered the development of DiHS/DRESS in our patients. In the current coronavirus epidemic, it might be important to assess mRNA-based COVID-19 vaccination status and date of vaccination when evaluating a patient with DiHS/DRESS.

Significance of IL36RN mutation analyses in the management of impetigo herpetiformis: A case report and review of published cases.

Impetigo herpetiformis (IH) is a rare variant of generalized pustular psoriasis (GPP), which develops during pregnancy. GPP is associated with mutations of IL36RN, but it is still unclear whether the same is true of IH. A 20-year-old Japanese woman developed erythema and pustules on her trunk during the 27th week of her first pregnancy. Within 1 month, the skin lesions spread over her whole body, accompanied by fever. Skin biopsy revealed Kogoj's spongiform pustules in the epidermis and she was diagnosed with IH. Systemic administration of prednisolone failed to resolve the skin eruption, but it was partially improved by the addition of cyclosporin. The patient gave birth to a healthy female infant. After delivery, her erythema relapsed and the effect of granulocyte and monocyte adsorption apheresis was limited. Thus, secukinumab was administrated, and since then, she has maintained complete remission. Mutation analysis revealed a homozygous c.28C>T (p.Arg10X) mutation in IL36RN. Twelve cases of IH, including that presented here, have been reported together with the results of IL36RN genetic analyses, and 10 of the 12 cases occurred in East Asia (Japan and China) despite the fact that IL36RN mutations in GPP have been reported worldwide. Among 10 IH patients of East Asian descent, seven had IL36RN mutations, all of which were founder mutations causing GPP in East Asia: c.28C>T (p.Arg10X) or c.115+6T>C (p.Arg10ArgfsX1). Thus, East Asian founder mutations may play an important role in the pathogenesis of IH. IH patients with IL36RN mutations have a tendency to require biologics to resolve postpartum flare-ups or sustained psoriatic skin lesions. Because IL36RN mutation status may help predict postpartum flare-ups in IH patients, mutation analysis should be considered to enable preparation for biologic therapy of intractable flare-ups.

Benign neonatal hemangiomatosis with early regression of skin lesions: A case report and review of the published work.

A 2-day-old Japanese male infant was referred to our outpatient clinic for multiple cutaneous hemangiomas present since birth. Physical examination revealed 14 small, well-circumscribed red papules, scattered over the head, face, dorsum of the right hand, trunk, lower extremities, buttocks and penis. Ultrasound examination revealed no evidence of visceral involvement. Histological examination of a cutaneous lesion was consistent with infantile hemangioma, resulting in the final diagnosis of benign neonatal hemangiomatosis (BNH). The hemangiomas enlarged by 1 month of age and began to resolve at 2 months of age. Within the next month, the lesions had almost completely disappeared. BNH is a rare, non-heritable, self-limited, benign disease characterized by multiple cutaneous infantile hemangiomas and no or unremarkable visceral lesions. Generally, BNH lesions spontaneously regress within the first 1-2 years of life or within 4 months of onset. However, there have been no detailed reports about the time course of BNH. To our knowledge, 31 cases of BNH without hepatic hemangiomas, excluding this case, have been reported so far. Twenty-one of these cases demonstrated spontaneous regression of the cutaneous hemangiomas without treatment. In all cases, the cutaneous hemangiomas were present at birth. The median age at the beginning of spontaneous regression was 6.0 months (range, 1-12) and the median age at complete or almost complete regression was 15 months (range, 3-28). Cutaneous hemangiomas in BNH without hepatic hemangiomas undergo spontaneous regression within the first year of life.

Subcutaneous dermoid cysts on the eyebrow and neck.

We report a case of dermoid cysts on the right lateral eyebrow and anterior neck. Multiple concurrent dermoid cysts, as in the present case, are very rare. The differential diagnosis of dermoid cyst includes epidermoid (epidermal inclusion) cyst, trichilemmal cyst, pilomatrixoma, lymphatic malformation, and lipoma. In particular, thyroglossal duct cyst and midline anterior neck inclusion cyst are part of the differential diagnosis when the lesion is in the anterior neck.

Two cases of cutaneous gnathostomiasis after eating raw Salangichthys microdon (icefish, shirauo).

Cutaneous gnathostomiasis (CG) is a disease caused by ingestion of third-stage Gnathostoma larva in raw snakes, freshwater fish or frogs. The common causative organisms of CG in Japan include G. nipponicum, G. spinigerum, G. doloresi, G. binucleatum and G. hispidum. We report two cases of CG after eating many raw Japanese icefishes (Salangichthys microdon). In both cases, linear itchy eruptions on the trunk developed after eating many S. microdon. We performed genetic analysis in the first case, which revealed G. nipponicum. Of note, this is the first case of CG diagnosed based on genetic analysis in Japan. In Japan, eating whole small raw freshwater fish is common. The most popular types of raw small freshwater fish consumed in Japan are S. microdon (shirauo in Japanese) and Leucopsarion petersii (shirouo in Japanese). Usually, S. microdon are born in rivers, but live in both the sea and rivers. They feed on small fish and freshwater water fleas and spawn in rivers in the spring. On the other hand, L. petersii are born in rivers, but move to the sea soon after hatching. They feed on plankton such as copepod in the sea. They do not feed on anything when they return to rivers to spawn in the spring. Therefore, we hypothesize that S. microdon are more easily parasitized by G. nipponicum.