Emphysematous osteomyelitis of the acetabulum in an immunocompetent male child caused by gram-positive cocci: a hitherto rarely reported association.

Emphysematous osteomyelitis is a rare and potentially life-threatening form of osteomyelitis characterized by intraosseous gas. In the absence of prior surgery or open fracture, it is most commonly seen in immunocompromised adults and associated with gram-negative organisms. We report a rare case of acetabular emphysematous osteomyelitis in a 12-year-old immunocompetent male child. Marrow signal alteration with soft tissue collection involving the right acetabular area of pelvic bones was seen on contrast-enhanced magnetic resonance imaging. Computed tomography (CT) demonstrated intraosseous air foci with the characteristic pumice stone sign, confirming the diagnosis. Culture grew methicillin-sensitive Staphylococcus aureus. The patient was successfully managed with surgical debridement and antibiotic therapy. Early CT-based diagnosis and prompt management are crucial for improving outcomes in this rare condition.