A previously well 12-year-old boy presented after 1 month of increasing right-sided hip pain with a limp, decreased energy and a 2-kg weight loss. He had no history of trauma, other joint problems, ...

Figures 1-2. Magnetic resonance images demonstrate an 8- x 4-cm abscess in the right psoas muscle and an area of high signal in the right psoas and iliacus muscle.