Mpox Case Presenting With Genital Lesions and Proctitis

Monkeypox (Mpox) is a zoonotic Orthopoxvirus of the Poxviridae family, endemic to Africa. In August 2022, the US government declared it an emergency because of the worldwide spread. Traditionally, Mpox infection spreads through contact with infected animals. However, the 2022 outbreak Centers for Disease Control and Prevention (CDC) data note that 94% of cases had recent male-to-male sexual or close intimate contact, suggesting a novel sexual transmission. In this article, we report a 39-year-old HIV-positive man presenting with a diffuse cutaneous rash, perianal pain, and bloody stool of 2-week duration. A medical history includes intravenous drug use and multiple sexual partners. Physical examination revealed umbilicated, tan-colored, crusted cutaneous papules scattered across the face, trunk, and genital regions. Perianal lesion biopsy showed an acanthotic epidermis with spongiosis, ballooning degeneration of keratinocytes, and the formation of multinucleated syncytial keratinocytes. A dermal superficial/lichenoid mixed inflammatory cell infiltrate with multinucleated giant cells was noted. Perianal lesion polymerase chain reaction (PCR) was positive for Mpox. Colonoscopy revealed a 3-cm circumferential rectal ulcer with gray exudate and necrosis. A rectal ulcer biopsy showed an ulcerated mucosa with acute proctitis and necrosis. There were scattered macrophages with intranuclear inclusion and glassy vacuolization, and Mpox infection was confirmed by immunostaining with a Mpox-specific anti-Vaccinia virus antibody.