Diffuse villonodular synovitis of the knee joint in childhood

Bulgarian Medical Journal, 2025, 19(3), 68-71

S.Nikolova¹, D.-N. Nenov¹, Z. Petrova², P. Georgiev¹

1 Department of Orthopedics and Traumatology, Faculty of Medicine, Medical University ‒ Sofia
2 Institute of Experimental Morphology, Pathology and Anthropology with Museum, BAS ‒ Sofia

Abstract. Purpose: The study purpose is to analyze cases with diffuse, locally aggressive villonodular synovitis in children and adolescents. Clinical Case Descriptions: Four cases of the particular neoplasm, in children with a mean age of 8.7 ± 5.9 years (4.5-15.6) at the time of treatment, are presented. Three of the cases are diagnosed in the last 24 months which we accept as an atypical rise in incidence. In all patients, the diagnosis is delayed by 22.7 ± 16.7 months (7-3) due to a primary misdiagnosis. The clinical signs include a painful monoarthritic form of knee synovitis with hydrops and a limited range of motion. Diagnosis is based on MRI evaluation. All children have undergone anterior arthrotomy and subtotal synovectomy. In three of the cases with a mean follow-up period of 4.7 years (6 months–13 years), the range of motion is completely restored, there is no pain and no evidence of recurrence of on the 6th and 18th postoperative month. In one child, with the youngest age, the diagnosis is delayed by more than two years, there is no recurrence postoperatively, but there is a persisting formation in the dorsal part of the joint, as well as limited range of knee motion. A dorsal synovectomy is yet to be performed. In all cases, intraoperative findings fully confirm the diagnostic imaging and its high specificity. Histological results of the finding are very typical for the neoplasm. Conclusion: Due to the low incidence and the broad spectrum of differential diagnoses of monoarthritis, the neoplasm creates diagnostic difficulty along with a delay in the successful surgical treatment. Hence, we recommend MRI in all children with monoarticular knee arthropathy that persists for more than 30 days.

Key words: diffuse villonodular synovitis, knee monoarthritis, children, synovectomy

Address for correspondence: Sofia Nikolova, MD, e-mail: sf_nikolova@yahoo.com