Objective To study the clinical features,pathogenesis,diagnosis and diferential diagnosis,and treatment options of pachydermodactyly.Methods The clinical data,laboratory test results,joint involvement,image characteristics,pathology interpretations,treatment methods and follow-up results of 12 cases of pachydermodactyly treated between 2006 and 2012 were analyzed.Results There were 10 males and 2 females with a mean age of 14 years.Clinical features included chronic painless swelling and enlargement of the PIP joints.Joint movement was normal.Joint involvement was symmetrical with bilateral 2,3,4 PIP joints most affected.Lab results were all negative.X-ray showed only peri-articular soft tissue swelling without bone and articular damage.MRI showed soft tissue swelling outside the joint capsule with no articular cartilage damage or synovitis.Histopathology showed increased dermal accumulation of collagen fibers.The course of the disease was benign.No treatment was needed except surgeries to improve the aesthetics.Conclusion Pachydermodactyly is an uncommon disease,which is not familiar to most hand surgeons.It should be differentiated from other arthritis involving PIP joints.Correct diagnosis of this disease entity can avoid over treatment. Key words: Diagnosis, differential; Finger joint; Pachydermodactyly