Brodie's abscess in the ischium of a pediatric patient: a case report.

Osteomyelitis, a bone infection, is rare in the pelvic bones of children, particularly in the ischium, with few documented cases in the literature. Staphylococcus aureus is the most common causative agent. Brodie's abscess, a subacute form of osteomyelitis, primarily affects boys and is challenging to diagnose, as it may be mistaken for bone tumors due to its insidious clinical presentation. Brodie's abscess causes bone destruction, bone marrow edema, and complications in soft tissues and joints. Diagnostic methods such as magnetic resonance imaging, which reveals the "penumbra sign", and needle biopsy are essential for diagnosis. Treatment involves prolonged antibiotic therapy and, in some cases, surgical drainage. Malignant tumors, avulsions, and inflammatory conditions, such as ischial osteitis, should be excluded in the differential diagnosis. The objective of this report is to describe a rare case of subacute osteomyelitis in the ischial bone of a pediatric patient, highlighting the imaging, laboratory findings, and clinical manifestations observed.