Giant Cell Tumor of the Tendon Sheath in the Knee of an 11-year-old Girl

Giant cell tumors of the tendon sheath (GCTTS) most commonly occur in the flexor tendon sheath of the hand and wrist, followed by the ankle and foot region. GCTTS in the knee joint is rare, particularly in children. The rate of occurrence in the adult knee is approximately 1.8 in each 1 million, but this includes both the localized form (GCTTS) and the more diffuse intra-articular form known as pigmented villonodular synovitis (PVNS).1 Gholve et al2 reported on 29 children with GCTTS, but only 1 male and 1 female, both aged 16 years old, had a tumor in their knee. Ushijima et al3 had 207 patients, 8 with GCTTS in their knees, while Rodrigues et al4 had 28 patients, 4 with GCTTS in their knees. However, neither reported whether these were adults or children. The clinical importance of the tumor is highlighted by the fact that the symptoms of the disease are nonspecific.5 Here, we highlight an interesting case of giant cell tumor (GCT) occurring in a child who presented to our outpatient department. Clinical knowledge of the presentation of a GCT may be beneficial for clinicians. Case Report