Adverse reaction to metallic debris (ARMD). A 70-year-old female with left hip resurfacing complicated by pseudotumour formation. Axial T2 pelvis with metal artefact reduction technique demonstrating distension of the left hip pseudocapsule posteriorly (dotted line) and a larger anterior pseudocapsule defect decompressing into the iliopsoas bursa (arrow). This thickened, T2-hypointense rim with synovial proliferation favours pseudotumour/ARMD over infection.