Hip chondrolysis due to enthesitis-related juvenile idiopathic arthritis treated successfully with adalimumab: A case report.

Coxitis with rapid hip chondrolysis in juvenile patients requires careful diagnosis and treatment. This report describes a case that was initially diagnosed as idiopathic hip chondrolysis but finally diagnosed as enthesis-related juvenile idiopathic arthritis (JIA). Case: A 15-year-old boy complained of bilateral hip pain and difficulty in walking. Initially, a diagnosis of idiopathic hip chondrolysis was made based on the imaging findings of centralised joint space narrowing on plain radiography and high-signal areas in the femoral head and acetabulum on T2-weighted fat-suppressed magnetic resonance imaging (MRI) without joint effusion. After the patient was admitted to our hospital, a diagnosis of enthesis-related JIA was made. Enthesis-related JIA was suspected based on arthritic changes in the sacroiliac joints that were detected incidentally during computed tomography and MRI. After initiating adalimumab administration, MRI revealed the disappearance of abnormalities in the acetabulum and femoral head. Moreover, the hip pain and contracture gradually improved, and the patient could return to daily activities without pain. Our report highlights the importance of awareness regarding the possibility of enthesis-related JIA in juvenile patients presenting with coxitis and rapid chondrolysis of the hip joint without joint effusion.