RESUMO
Mpox virus infection (MPXV) has recently been recognized as a public health emergency by the World Health Organization. While several studies have described the clinical characteristics of MPXV-oral lesions, there remains a dearth of information regarding the histological and ultrastructural oral findings. A 24-year-old HIV-positive man presented with a shallow ulcer, covered by a fibrinoid membrane, and surrounded by an erythematous halo in the hard and soft palate. The clinical appearance of the lesion raised suspicion of a viral infection; thus, the diagnosis was based on histological and electronic microscopy findings and confirmed by RT-PCR testing in the skin specimen. This case report aims to offer comprehensive insights into the clinical, histopathological, and ultrastructural features of oral lesions caused by MPXV in an individual with HIV. This report provides valuable information about the characteristics of MPXV infection in the oral mucosa, particularly in people living with HIV.