Aim of this paper is to discuss, on the basis of an extensive critical review of the recent literature, the case of a 56-yr-old male patient who suffered from cutaneous psoriasis and psoriatic arthritis mutilans (PA) (polyarticular, symmetric, destruent and erosive) with involvement of the hands, feet and spine, associated with android obesity and mild type 2 diabetes mellitus. HLA typing of the patient showed the HLA-A3-Ax, B14-B63 and Cw4-Cw6 haplotypes, some of which are associated or correlated with susceptibility to PA. Cutaneous psoriasis is a chronic inflammatory dermatitis, with onset at any age and affecting approximately 2% of the western populations. In 5-7% of patients, it is associated with articular manifestations or true arthritis. PA is a chronic, inflammatory, seronegative arthropathy which may develop in some psoriasis patients, may involve peripheral and axial (spondarthritis) joints and may lead to severe joint destruction. Genetic, immunologic and environmental (i.e., infectious agents or trauma) factors seem to play an important role in the onset and clinical appearance of PA. Although PA is a clinically monomorphic disease, it may show different heterogenous subgroups with differences in their etiopathogenesis. When PA is suspected, it is mandatory to analyze carefully the patient's familiar history, search attentively for the specific skin features, exclude a septic arthritis (especially if the involvement is monoarticular) and, in the cases of fulminant disease, consider always the possible coexistence of an acquired immunodeficiency syndrome. PA can occasionally be an aggressive, disfigurating and disabling disease and the treatment (incisive and precocious) should be similar to that for rheumatoid arthritis. At present, a definitive therapy does not yet exist, but the majority of PA patients can lead a fairly normal life and they do not show increased mortality rates (excluding the severe cases of erythrodermic or pustulosis psoriasis). However, as a result of the various problems of occupation and morbidity it causes, PA is a disease with great social involvement.