Pharyngo-tonsillar involvement of Mpox in a cohort of men who have sex with men (MSM): A serious risk of missing diagnosis.

During the 2022-outbreak, peculiar clinical presentations of Mpox have been described, some of which can make the diagnosis of the disease extremely challenging. Here we report a case series of fourteen patients with Mpox pharynogotonsillar involvement (PTI) seen at National Institute for Infectious Diseases, "Lazzaro Spallanzani", in Rome, Italy from May to September 2022. All included patients were men who have sex with men (median age 38 years) reporting unprotected sex within three weeks from symptoms onset. Seven out of fourteen patients needed hospitalization due to uncontrolled pain, reduced airspace and difficulty swallowing, of whom five were effectively treated with tecovirimat or cidofovir. The remaining two patients were treated with symptomatic drugs. The typical Mpox muco-cutaneous manifestations were not observed simultaneously with PTI in three patients, two of whom developed the lesions after several days, while one never manifested them. Polymerase Chain Reaction (PCR) for Mpox virus was positive in oropharyngeal swab, saliva and serum. Although PTI occurs in only a small percentage of Mpox cases, its diagnosis is of utmost importance. In fact, this localization, if not identified, could lead to serious complications in the absence of early antiviral treatment and to missed diagnosis with an increased risk of disease transmission.