From juvenile idiopathic arthritis to pachydermodactyly: a case report

Pachydermodactyly is a benign form of digital fibromatosis that predominantly affects the proximal interphalangeal joints of young males. The exact etiology is still unknown. The main concern about pachydermodactyly is its rarity and being misdiagnosed as juvenile idiopathic arthritis. The aim of the current paper is to report a case of pachydermodactyly that had been misdiagnosed as juvenile idiopathic arthritis with no response to treatment. A 19 year-old North African male presented with painless symmetrical swelling of the 2nd, 3rd and 4th proximal interphalangeal joints of both hands, and the right 5th proximal interphalangeal joint. The condition started 4 years ago when he was working as a baker. He was diagnosed as juvenile idiopathic arthritis and received treatment with no improvement. There were no morning stiffness, uveitis, limited function or history of trauma. All laboratory tests were negative. Plain X ray showed only soft tissue swelling around the joints. Ultrasound showed no signs of inflammatory synovitis, effusion or bony erosions. Pachydermodactyly diagnosis was considered. The patient was advised to decrease the rate of repetitive hand movements and to reduce the number of working hours. At 6-months follow up, the condition was completely stable with no progression. The comprehensive understanding of the characteristic clinical features of pachydermodactyly will contribute to the avoidance of misdiagnosis and unnecessary treatments. Ultrasound helps in the differentiation between pachydermodactyly and juvenile idiopathic arthritis.