Hematogenous osteomyelitis with inflammatory cyst formation mimicking a soft-tissue tumor

Reported is a case of hematogenous osteomyelitis of the femur with inflammatory cyst formation mimicking a soft-tissue tumor. A 15-year-old boy with a three-year history of a gradually enlarging soft-tissue mass of his left thigh was found to have an aborted acute hematogenous osteomyelitis complicated by an inflammatory cyst that was probably caused by inadequate antibiotic therapy. The osteomyelitis and its inflammatory cyst were treated with excisional debridement and six weeks of antibiotic therapy. The patient remains well five years later, with no clinical or radiologic evidence of recurrence. This is a new variant of chronic osteomyelitis that has not previously been reported.