Synovial hemangioma of the knee joint in pediatrics: our case series and review of literature.

BACKGROUND: Synovial hemangioma is a benign intra-articular tumor. This condition is rare and unfamiliar soft tissue tumor to most orthopedic surgeons. Delayed diagnosis causes osteoarthritic damage and the destruction of joint structures due to infiltrating tumor growth. We discuss the patterns of tumor location and the appropriate surgical procedure for this condition.

METHODS: Ten patients were treated surgically in our department. These comprised five males and five females ranging in age from 0 to 17 years (average age 12.4 years). Preoperative diagnosis was made using clinical findings, plain radiographs and magnetic resonance imaging. The follow-up time after surgery was at least 3 years.

RESULTS: The main symptom was pain. Three cases revealed hemarthrosis. The range of motion of the affected knee joint was limited in five cases. The average time between onset of pain and diagnosis was 3 years. Tumor location was classified into three patterns: (1) anterior patellofemoral joint type in five, (2) posterior popliteal type in two and (3) diffuse proliferation type in two. Open arthrotomy with synovectomy was performed in all cases. No tumor recurrences were experienced after a minimum follow-up of 3 years.

CONCLUSION: Clinical symptom and magnetic resonance imaging are helpful to obtain the diagnosis and determine the extent of the lesion. Depending on the tumor location, synovial hemangioma in the knee joint can be classified into patellofemoral, popliteal and diffuse types. Open arthrotomy with sufficient tumor and synovectomy is important to prevent tumor recurrence.