Case Report and Literature Review of 10 Pediatric Cases of Knee Pigmented Villonodular Synovitis.

Objective: This study was aimed to analyze 10 pediatric cases of pigmented villonodular synovitis (PVNS) of the knee to elucidate their clinical features, diagnosis, treatments, and prognosis for providing reference regarding its clinical management in children.

Methods: A retrospective analysis was made pertaining to the clinical manifestations, magnetic resonance imaging (MRI) findings, pathology, immunohistochemical results, treatment methods, and follow-up outcomes of 10 pediatric PVNS patients of the knee treated from January 2022 to January 2024 at our hospital. They were compared and analyzed with existing literature.

Results: (1) All 10 patients had joint swelling with restricted movement, mainly in older female children with male-to-female ratio of 3:7 and average age of 14.1 ± 3.6 years; (2) diagnostic positive rate of MRI was 80%; (3) significant features of PVNS were the appearance of villous and nodular hyperplasia on synovial surface and deposition of brownish-yellow granular hemosiderin. Immunohistochemical staining results were clusterin (synovial cells+), D2-40 (synovial cells+), CD163 (histiocytes+), KP-1 (histiocytes+), CD31 (vascular+), P63 (-), and Ki67 (+, 1%-10%); and (4) all patients underwent arthroscopic surgery with 20% recurrence rate.

Conclusion: Pediatric knee PVNS is more prevalent in older female children. The PVNS diagnosis is carried out by MRI, pathology, and immunohistochemistry. Arthroscopic surgery is effective for treating this condition in children.