No abstract

We describe two Japanese female patients with pigmented extramammary Paget's disease (EMPD); one patient had a dark brown plaque and the other had a reddish patch with a pigmented area, both affecting the vulval region. Histochemical and immunohistochemical examinations confirmed EMPD with melanocyte colonization; plump tumour cells with a large nucleus and pale cytoplasm that were positive for CAM 5.2 and CEA proliferated singly or in nests in the epidermis, and scattered among the tumour cells were many dendritic cells with a large amount of melanin that were positive for HMB-45 and S-100 protein. Fontana-Masson (FM) stain showed many positive cells with well-developed dendritic processes within and around tumour nests. Histochemical and immunohistochemical studies of non-pigmented EMPD cases on the same region showed that HMB-45 positive cells were sparse or not detected at all, and that also FM staining-positive cells were decreased or not detected, and their dendritic processes were poorly formed. The present study suggests that there might be heterogeneity in EMPD in terms of relationships between Paget's cells and melanocytes.

The solitary skin lesions of IgG(4)-related disease were similar histologically and immunohistochemically to the skin lesions of Kimura's disease. The concept of IgG(4)-related disease may help clarify the pathomechanism of diseases of unknown aetiology that possess features of IgG(4)-related disease.

A 65-year-old man experienced cough and shortness of breath 3 days after receiving the first dose of the Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccine. Chest X-ray revealed bilateral infiltrates, and the desaturation deteriorated rapidly. The symptoms and radiographic abnormalities rapidly improved after the initiation of corticosteroid therapy. Intradermal testing of the Pfizer-BioNTech COVID-19 vaccine showed a delayed positive reaction. Based on these findings, the patient was diagnosed with COVID-19 vaccineinduced pneumonitis. The timing of the onset of pneumonitis after vaccination and the results of intradermal testing suggest that Type IV hypersensitivity against COVID-19 vaccine may have been responsible for this clinical condition.

Eighteen patients with adult-onset Still's disease have been followed up for 3-22 years in our department. Initial manifestations were fever with skin rash in 14 patients, fever, skin rash and sore throat in two, skin rash in one and arthralgia in one. During the follow-up period, typical skin rash was seen in all patients, of them five patients (29%) revealed atypical skin rash simultaneously. Atypical rash included persistent erythema with pigmentation in two, persistent plaques and papules with linear erythema in two and edema of the eyelids mimicking dermatomyositis in one. Persistent papules and plaques revealed histologically characteristic features, such as dyskeratotic keratinocyte and liquefaction degeneration as well as a sparse superficial dermal infiltrate containing scattered neutrophils. In patients of chronic articular type and polycyclic systemic type, atypical skin rash, lymphadenopathy and hyperferritinemia were noted to be significantly higher than those of monocyclic type. These factors might be prognostic factors of adult-onset Still's disease in our study.