Pachydermoperiostosis is a rare disease characterized by clubbing, periostosis, and soft tissue swelling, caused by mutations in any of the genes involved in prostaglandin metabolism (SCLO2A1 and HPDG). Disease may also cause inflammatory arthritis and included in the differential diagnosis of juvenile chronic arthritis. A 17-year-old boy presented to our pediatric rheumatology outpatient clinic with the complaints of pain and swelling in bilateral knees and ankles that has been present for one year but got worsened in the last month. On phys- ical examination he had rough face with furrowing of skin on face and scalp, and clubbing on all digits. A homozygote mutation detected on SLCO2A1 gene and patient was diagnosed as primary complete pachy- dermoperiostosis. Herein, we presented a pediatric case with inflam- matory arthritis, diagnosed as pachydermoperiostosis based on clinical and radiological findings.