Occult axial involvement in patients with psoriatic arthritis mutilans: a case report.

We present the case of a patient with psoriatic arthritis (PsA) mutilans and occult axial involvement. The patient had suffered from PsA mutilans for more than a decade, with severe residual articular damage, but had been in clinical remission for years. Clinical axial involvement was never reported; however, magnetic resonance imaging of the sacroiliac joints, performed for other reasons, documented active inflammation and damage even without clinical symptoms. These findings corroborated the hypothesis that axial involvement could be asymptomatic, subclinical and, furthermore, underdiagnosed or even occult in patients with PsA mutilans, in which cases it should be carefully evaluated.