Localized Giant Cell Tumor of the Tendon Sheath: A Rare Case of Anterior Knee Pain

Abstract

This report describes a 61-year-old female with a giant cell tumor of the tendon sheath (GCT-TS). MRI showed that an elliptical abnormal signal was observed over the infrapatellar region of the right knee. We directly do arthroscopy to remove the tumor. An oval irregular mass of about 2.0 cm × 1.5 cm × 1 cm in the right knee joint was found. It was hard and had a dark red surface and the pedicle of the mass was connected with the joint capsule and infrapatellar fat pad. Nodular GCT-TS occurs less frequently in large joints than the small joints of the fingers and toes. The current report demonstrates the unique characteristics of the GCT-TS that extends around the ankle and invades the knee and proximal humerus.