A very rare case of spontaneous rupture of the tibialis anterior tendon diagnosed by MR imaging is presented. The tendon rupture occurred in a patient with recent onset psoriasis of both shins who used a corticosteroid cream (0.1% of methylprednisolone aceponate) for his skin lesions during the last 3 months before the incident causing tendon rupture. This is the first report of a spontaneous tendon rupture in a patient with psoriasis.