[Psoriatic onycho-pachydermo-periostitis of the big toe. Anatomo-clinical study and physiopathogenic approach apropos of 4 cases].

The authors report 4 cases of rheumatoid psoriasis in which involvement of the great toe, associating psoriatic onychosis, thickening of the distal soft tissues and osteo-periostitis of the distal phalanx without lesions of the interphalangeal joint, is the result of a direct repercussion of the ungual lesion on the distal phalanx. This is explained by very close anatomic links between nail and distal phalanx. They advocate the term of psoriatic onycho-pachydermo-periostitis of the great toe or OP3GT, when referring to this radio-clinical syndrome highly evocative of rheumatoid psoriasis.