Osteoarthropathia psoriatica of one leg: a manifestation of somatic mosaicism?

A psoriatic osteoarthropathy localized in the left quadrant of a male patient is described. Diagnosis was made on the basis of bone scintigraphy (specific distribution pattern) and histological evaluation of a bone biopsy. There is no indication of psoriasis in the patient's family. Nor is there an association to psoriasis-typical HLA markers. Psoriasis of the skin has not been found. Environmental factors, including a Köbner phenomenon on the skeleton resulting from a trauma 13 years ago (hallux rigidus operation), are discussed in connection with this manifestation. The genetic aspects of this unusual localization are considered.