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.

Dystrophic calcinosis cutis in a patient with cutaneous sarcoidosis in remission.

A 65-year-old Japanese woman was referred to our department because of a 5-month history of asymptomatic papules on the face. She was diagnosed with cutaneous sarcoidosis on the face 20 years ago. All of the lesions had completely disappeared with oral corticosteroids. Twenty years after the diagnosis of sarcoidosis, small papules developed in areas where the cutaneous sarcoidosis had been located. Physical examination revealed four yellow-white papules on the face. Dermoscopy revealed a homogenous, round, and yellow-white lesion. Serum levels of calcium and phosphorus were normal. Histopathology demonstrated calcium deposits in the dermis surrounded by inflammatory infiltrates without sarcoid granulomas. We made a diagnosis of calcinosis cutis. Basal cell carcinoma with calcinosis cutis, milia-like calcinosis cutis, and subcutaneous calcified nodule should be differentiated. Calcinosis cutis can be classified into four subtypes based on pathogenesis: dystrophic, metastatic, idiopathic, and iatrogenic. Dystrophic calcinosis cutis is caused by local tissue damage or abnormalities. Whereas, metastatic calcinosis cutis is often associated with hypercalcaemia, hyperphosphatemia, or hyperparathyroidism. There are reported cases of metastatic calcinosis cutis associated with sarcoidosis because patients with sarcoidosis often present with hypercalcaemia. However, dystrophic calcinosis cutis associated with sarcoidosis has been rarely reported. In the present case, systemic treatment for sarcoidosis may have degraded sarcoid granulomas and yielded necrotic tissue and dermal fibrosis, which might have induced ectopic calcification. Thus, we thought the present case consisted of dystrophic calcinosis cutis that developed in areas with cutaneous sarcoidosis in remission.

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.

Generalized self-consistent reservoir model for normal and anomalous heat transport in quantum harmonic chains.

Fictitious stochastic reservoirs incorporate scattering and dephasing mechanisms into the system in contact with these reservoirs. The reservoir-system coupling is described by the related self-energy in terms of the nonequilibrium Green's function formalism or equivalently the quantum Langevin equation formalism. In this study, we investigate thermal transport in a finite segment of an infinitely extended quantum harmonic chain with an equal self-energy at each site by using the self-consistent reservoir approach. In this setup, the entire system is lattice translation invariant so that mismatched boundaries are excluded from the model. Solving the Landauer-Büttiker equations under the self-consistent adiabatic condition, we quantitatively elucidate a thermally induced crossover of ballistic-to-diffusive transport and its scaling relation prescribed by a temperature-dependent mean free path. It is also shown that normal transport emerges in the diffusive limit for a linear self-energy, while nonlinear higher-order ones generically lead to anomalous transport. Physical implications of these observations are discussed in terms of the persistence of a massless Goldstone mode as well as the conservation of total linear momentum.