MRI findings of Monkeypox rash in a patient with suspected midfoot osteomyelitis

Background: Monkeypox (Mpox) is a viral illness that underwent a multinational outbreak in 2022-2023. Symptoms of this disease include fever, myalgia, headache, and lymphadenopathy, followed by the onset of a characteristic rash. Transmission of Mpox is typically through respiratory secretions or contact with skin lesions or bodily fluids. The diagnosis is made by PCR of skin lesions samples, but secondary features, such as lymphadenopathy, may be incidentally noted on radiologic imaging. Case presentation: A middle-aged male with a past medical history of uncontrolled HIV present-ed to the emergency department one week following the onset of a foot ulcer and rash. PCR testing confirmed the rash was due to Mpox, and the patient underwent appropriate treatment. Due to con-cern for osteomyelitis deep in the foot ulcer, an MRI of the foot was performed. While the MRI was negative for osteomyelitis, it incidentally included the skin lesions which corresponded to the pa-tient’s rash. Conclusions: This case demonstrates MRI findings of Mpox rash in a patient with suspected mid-foot osteomyelitis. While laboratory testing remains the appropriate confirmatory testing for Mpox in-fection, clinicians and radiologists should remain aware of the imaging appearance of these lesions, as well as other secondary findings we may encounter.