A 55-year-old female patient with a history of palmoplantar pustular psoriasis presented with a 12-month history of nail dystrophy that was followed by swelling and erythema of the right great toe for 6 months. She was otherwise well with normal baseline blood tests and chest X-ray. No improvement was evident with multiple courses of antibiotics.

Photographs of both left and right toes are shown in Fig. 1. As part of the diagnostic evaluation she had radiographs (Fig. 2) and a subsequent MRI scan (Figs. 3, 4).

Fig. 1
figure 1

Photographs of the right and left toes

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Fig. 2
figure 2

Radiographs. a Frontal and b lateral

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Fig. 3
figure 3

a Coronal T1W and b coronal T2W fat-suppressed MRI

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Fig. 4
figure 4

a Sagittal and b axial proton density MRI

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