Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood. Since there is no pathognomonic diagnostic criterion, the diagnosis is made by excluding other arthritis in childhood. Multiple Enchondromatosis, also known as Ollier’s disease, is an ossification disorder often seen in the metaphyseal and diaphyseal regions of long bones or the metaphyseal regions of tubular bones in the hands and feet. Pain, shortening, deformity, fracture, and transformation into malignancy may appear. Here we report a case with extended oligoarticular juvenile idiopathic arthritis (oligo JIA) who developed enchondromatosis during clinical follow-up. While the patient was in remission without medication, he presented with swelling in the hand fingers and enchondromatosis lesions with expansile lytic characteristics were seen on the radiograph. Comorbid diseases can be added in the clinical follow-up of JIA patients. Physical examination is important in terms of added comorbid disease. Our case report is important because it is the first case in which these two diseases are seen together in the literature.

Keywords: Deformity, enchondromatosis, Juvenile Idiopathic Arthritis