pigmented villonodular synovitis in a 15-month-old boy challenged the physicians for two years: a case report and literature review

Background: pigmented villonodular synovitis (pvns) is a very rare pathology of the synovial membrane and even less common in the pediatric group. rarity leads to misdiagnosis in pre-puberty cases, which may waste significant time for the patient before definite treatment. reviewing such cases is useful for every pediatrician or orthopedic surgeon to avoid misdiagnosing possible cases.case report: we report a 15-month-old boy who suffered pain and swelling in his knee for about two years before he was eventually diagnosed with pvns and underwent surgery. keeping this diagnosis in mind may have saved him and his family from two years of pain, several admissions, and unnecessary prescriptions.conclusion: pvns in pediatrics is rare, but it can occur and be misdiagnosed for diseases such as juvenile rheumatoid arthritis (jra) and septic arthritis which elongates the pain period. pvns responds well to subtotal synovectomy, and symptoms are relieved after the surgery if well performed.