This 16-years old girl presented with sacral pain. She had an aggressive looking lesion on MRI but without significant enhancement of the soft tissue and without much uptake in the soft tissue, though there was bone uptake and marked sclerosis. She had 3 biopsies, all negative for malignancy or a specific infection. Once she was labeled as chronic non-bacterial osteitis (CNO) and put on appropriate treatment, she improved clinically.

CNO encompasses the earlier terms of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO. It is a pediatric and adult auto inflammatory disorder that presents with multifocal or solitary sterile inflammatory bone lesions with bone pain and a waxing and waning clinical course.