A 33-year-old male presented with progressive atraumatic left ankle pain of 20 years duration. Clinical assessment revealed anterolateral ankle tenderness with stiffness at the subtalar joint. Ankle MRI was performed (Fig. 1).

Fig 1
figure 1

Left ankle MRI. Sagittal T1 (a), sagittal MRI SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with fat saturation (b, c), coronal PDFS (proton density with fat suppression) (d, e)