Tumours and tumour-like lesions of joints: Differential diagnoses in a paediatric population compared to adults.

objectiveTo determine the differential diagnosis of intra-articular tumours and tumour-like lesions in a paediatric population compared to adults.

methodsRetrospective review of children up to the age of 18 years with suspected intra-articular tumours and tumour-like lesions referred to a specialist musculoskeletal oncology service from January 2019 to August 2020. Data recorded included patient age and gender, lesion location and morphology (based on the classification system of Adams et al.), and the final diagnosis made either by image-guided biopsy/resection or by clinical and imaging features. Comparison was then made with a group of adults presenting during the same period.

results28 paediatric patients were included (12 males and 16 females with mean age 11.2 years, range 3-18 years). Joints involved were the knee ( ADVANCES IN KNOWLEDGEART: In our series, ~16% of tumours and tumour-like lesions of joints occur in the paediatric population. Tenosynovial giant cell tumour remains the commonest diagnosis in children as in adults. Synovial haemangioma and juvenile idiopathic arthritis were the next commonest diagnoses in children, while primary synovial chondromatosis and reactive synovitis were the next commonest diagnoses in adults. Malignant lesions are rare in both groups.