Buruli ulcer: a systemic disease.

We studied a 4-year-old boy from Angola who presented with 2 cutaneous ulcerations of the right hip and osteomyelitis of the left knee and right ankle. Mycobacterium ulcerans disease was confirmed by direct smear examination and by polymerase chain reaction. The patient was treated with antimycobacterial drugs, repeated surgical debridement, skin grafting, and daily hyperbaric oxygenation. Despite significant improvement of the local lesions in response to hyperbaric oxygenation, swelling of the right knee, without associated skin lesions, was noted. Radiological evaluation and open biopsy revealed extensive metaphyseal osteomyelitis of the right distal femur. A 99technetium bone scan revealed an additional focus in the diaphysis of the left humerus, without soft-tissue involvement. This case documents, for the first time (to our knowledge), the systemic spread of M. ulcerans, with subsequent multifocal osteomyelitis and secondary involvement of soft tissues and supports the hypothesis that low tissue oxygen levels promote hematogenous spread of M. ulcerans. Sickle cell anemia, with associated microthrombosis and microinfarction, may have contributed to tissue hypoxia.