Pachydermodactyly: A Rare Type of Macrodactyly as a Dermatological Sign of Compulsive Behavior and Repetitive Minor Trauma; a Case Report and Review of the Literature

Pachydermodactyly is a very rare type of macrodactyly. It clinically resembles juvenile rheumatoid arthritis, but it has a non-inflammatory etiology without bone, articular, or synovial involvement. In this study, we report the case of a 15-year-old boy with repetitive behavior diagnosed with a pachydermodactyly after evaluation of bilateral swelling of the proximal interphalangeal joints. Histologic examination revealed epidermal hyperorthokeratosis, thickening of the dermis with increased dermal collagen and absence of inflammatory cells. Pachydermodactyly is a very rare condition associated with compulsive behavior and results from repetitive minor trauma that causes localized proliferation of fibrous tissue. Pachydermodactyly is a dermatological sign of compulsive behavior and repetitive minor trauma, and it should be distinguished from other forms of joint enlargement to avoid unnecessary medicamentous treatment. Control examinations did not reveal clinically relevant worsening even without any treatment applied.