Sudden onset of severe anterior knee pain and knee locking during sleep

Excerpt

In 2013, the WHO revised the terminology for the family of lesions previously described as giant cell tumor of the tendon sheath and pigmented villonodular synovitis. The correct current terminology is tenosynovial giant cell tumors, further subclassified by the extent (localized or diffuse) and location (intra- or extraarticular) [1]. Intraarticular lesions are usually monoarticular and usually affect the knee [2]. The localized intraarticular lesion was formerly termed as localized pigmented villonodular synovitis. The diffuse intraarticular diffuse type affects the entire joint synovium, and patients typically present with a long history of pain, swelling, restricted movement and occasional hemarthrosis [2, 3]. Localized intraarticular tenosynovial giant cell tumor is characterized by limited involvement of the synovium presenting as an intraarticular nodule or mass, which can result in mechanical symptoms, including locking, as presented in our case [2, 4]. Localized intraarticular tenosynovial giant cell tumor of the knee is usually located in the meniscocapsular junction, anterior tibial eminence, intercondylar notch region or lateral recesses. It is rarely located in the fat pad, medial femoral condyle, mediopatellar synovial plica or inside a popliteal cyst [2, 3]. Infrequently, the pedicle can be subject to torsion, resulting in tumor infarction [2]. …