Kaposi Sarcoma mimicking pedal osteomyelitis in a patient with HIV

Kaposi Sarcoma (KS) is an angio-proliferative mesenchymal neoplasm that typically affects the skin. In the setting of AIDS, it is usually disseminated, commonly involving noncutaneous sites like oral cavity, lymph nodes, pulmonary, and gastrointestinal systems. Musculoskeletal system involvement by KS is rare, and when encountered, it typically involves the axial skeleton (vertebrae, ribs, sternum, and pelvis) and/or maxillofacial bones. This report describes an unusual case of a 44-year old patient with HIV, who presented with a foot ulcer that fit the typical clinical features of osteomyelitis until MRI of the foot demonstrated atypical findings that challenged the original clinical diagnosis. This case highlights the role that advanced diagnostic imaging plays in the diagnosis of musculoskeletal Kaposi Sarcoma and serves as a reminder to radiologists to include Kaposi Sarcoma in the differential of multifocal osteolytic lesions in patients with HIV.