Monkeypox: A Histopathological and Transmission Electron Microscopy Study.

The global outbreak of human monkeypox virus (hMPXV1) in 2022 highlighted the usefulness of dermatological manifestations for its diagnosis. Infection by the human monkeypox virus thus necessitated inclusion in the diagnostic repertoire of dermatopathology. To assess the histopathological and microscopical findings of cutaneous lesions related to hMPXV infection, we analyzed skin biopsies from patients with positive MPXV DNA polymerase chain reaction presenting with a typical course of hMPXV1 infection. The most prominent histopathological findings were ascribable to a pustular stage in which epidermal necrosis with areas of non-viable keratinocytes and a "shadow cell" appearance were evident; in some cases, the deep portion of the hair follicle and the acrosyringial epithelium were affected. The main cytopathic modifications included ballooning keratinocytes, followed by Guarnieri bodies and a ground glass appearance of the keratinocytes' nuclei, together with a dense mixed inflammatory cell infiltrate with prominent neutrophil exocytosis. Transmission electron microscopy analysis demonstrated viral particle aggregates in the cytoplasm of keratinocytes, without any involvement of the nucleus. Interestingly, we also found the presence of viral particles in infected mesenchymal cells, although to a lesser extent than in epithelial cells. Through this study, we contributed to expanding the histological and microscopic knowledge of the human mpox virus, a key step to understanding current and potential future trends of the disease, as well as of other Orthopoxvirus infections.

Disseminated superficial actinic porokeratosis following hydroxyurea treatment: A case report.

Porokeratosis encompass a group of acquired and familial, preneoplastic, keratinization disorders, clinically characterized by atrophic macules or patches with a peripheral keratotic rim, the cornoid lamella. Genetic background is recognized as crucial in its pathophysiology, while immunosuppression and ultraviolet radiation represent triggering factors. We report the case of a woman who developed disseminate superficial actinic porokeratosis following the intake of hydroxyurea for a polycythaemia vera. Clinical, dermoscopic and histopathology data are showed, and the role of drug as a second-hit mutation trigger is discussed.

Circumscribed Morphea of the Scalp: An Entity to Be Considered in the Differential Diagnosis of Cicatricial Alopecia.

Introduction: Morphea, also known as localized scleroderma, could affect the head and neck region, mainly manifesting in a linear pattern. Localized scleroderma of the scalp presenting as a circumscribed alopecic patch has been described as an unusual clinical entity. We present a new case of circumscribed morphea of the scalp. Case Report: We present the case of a 33-year-old man with a single cicatricial alopecic patch of the scalp. The main clinical, trichoscopic, and histopathological findings are described. Conclusion: We suggest considering scalp morphea in the differential diagnosis of mono-lesional cicatricial alopecia involving the scalp.

Juvenile gangrenous vasculitis of the scrotum: Is it a variant of pyoderma gangrenosum?

Juvenile gangrenous vasculitis of the scrotum was described by Piñol et al in 1974 as a unique variant of scrotal gangrene of unknown origin, occurring exclusively in young individuals. It was characterized by an acute onset of skin ulcers undergoing complete resolution after appropriate therapy, with no relapses. We present a typical case of this extremely rare disease affecting a 16-year-old boy in whom the scrotal ulcerations were preceded by an episode of pharyngitis with fever. The condition promptly regressed after administration of intramuscular betamethasone in combination with oral ciprofloxacin. According to Piñol et al, juvenile gangrenous vasculitis of the scrotum, although poorly known to dermatologists, should be regarded as a distinctive entity within the wide group of scrotal gangrenes. On the other hand, the hypothesis that this condition may well represent a variant of pyoderma gangrenosum is discussed.