Prevalence of cranial involvement in a cohort of Italian patients with chronic non-bacterial osteomyelitis.

Chronic non-bacterial osteomyelitis (CNO) is a non-infectious inflammatory disease characterised by uni- or multi-focal bone lytic lesions. CNO mainly affects metaphysis of long bones, pelvis and shoulder girdle. Neurocranium lesions are extremely rare. The objective of the study is to describe the prevalence and clinical manifestations of CNO patients with neurocranium involvement in an Italian cohort of CNO patients. This is a retrospective study. Medical records of patients with CNO admitted to eight paediatric rheumatology centres were reviewed. Among 86 patients with CNO enrolled in the study, three of them were female and presented neurocranium involvement - multifocal lesions. Two out of the 3 patients were completely asymptomatic for cranial involvement, while one of the 3 complained of cranial bossing. Cranial involvement was detected with bone scintigraphy and then confirmed by magnetic resonance imaging and/or computed tomography. Two patients presented fever and two with skin manifestations. Laboratory inflammatory markers were increased in two of them. All patients underwent bone biopsy confirming the diagnosis. They all received NSAIDs. Two patients received corticosteroids and then methotrexate and achieved clinical remission, while one patient received pamidronate. This is the first report of neurocranium involvement in a cohort of patients affected by CNO. In our cohort no patient showed significant signs attributable to cranial involvement.