Chronic Recurrent Multifocal Osteomyelitis (CRMO) in Disguise: A Case Report

Chronic Recurrent Multifocal Osteomyelitis (CRMO) is an uncommon inflammatory bone disorder in children, characterised by sterile lesions and a relapsing course. Because its presentation overlaps with infection and malignancy, diagnosis is often delayed, especially in regions where tuberculosis is prevalent.

A 12-year-old boy presented with a 3-month history of intermittent fever, progressive lower-limb pain, and difficulty in walking. The illness was marked by migratory joint involvement and weight loss. Examination showed localised tenderness and restricted joint movement. Laboratory evaluation revealed anaemia and elevated inflammatory markers, while microbiological and autoimmune investigations were negative. Imaging demonstrated erosive and mild osteosclerotic changes on radiographs and multifocal marrow oedema on whole-body MRI involving the femora, pelvis, and sacroiliac joints without abscess or bone destruction. Bone marrow examination excluded infection and malignancy. Based on clinical and radiological findings, this study made a diagnosis of CRMO. Initial treatment with non-steroidal anti-inflammatory drugs provided partial relief. Because the disease persisted, corticosteroids and methotrexate were introduced, resulting in marked clinical improvement and recovery of mobility. At 6 months of follow-up, the child remained asymptomatic, with improvement of inflammatory markers and no further relapse.

CRMO should be considered in children with chronic bone pain and sterile inflammatory findings. Early recognition and appropriate imaging are essential to avoid misdiagnosis and prevent long-term complications. Whole-body MRI is valuable for demonstrating multifocal disease and supporting early diagnosis, thereby avoiding unnecessary antimicrobial therapy and invasive investigations.