Iliolumbar ligament ossification as a radiologic feature of reactive arthritis

We describe the case of a 21-year-old woman with the clinical picture of HLA-B27+ reactive arthritis (ReA) in whom the ossification of the left iliolumbar ligament was detected. Our case proves that ligament calcifications, which have so far been ascribed to diffuse idiopathic skeletal hyperostosis may also occur in young patients with ReA not primarily affected by metabolic osteoarticular diseases with negative family history.