Peripheral Vascular Compression in a Patient With Diffuse Tenosynovial Giant Cell Tumor of the Knee: A Case Report Focusing on the Role of the Ultrasound.

Tenosynovial giant cell tumors (TGCTs) are benign histo-fibrocystic tumors originating from the synovium of joints, bursae, or tendon sheaths. They are categorized into localized and diffuse types, each with distinct clinical presentations and management approaches. The diffuse form, which is rare, generally affects a single joint and is characterized by joint swelling, pain, functional limitation, and often hemarthrosis. While MRI is commonly used for diagnosis, we present a case highlighting ultrasound's significance in diagnosing and managing TGCTs, particularly for identifying vascular complications. A 59-year-old female with a 10-year history of recurrent swelling, pain, and functional limitation of the right knee was evaluated for persistent symptoms and unilateral right peripheral edema. Ultrasound revealed multiple hypoechoic, vascularized masses with both homogeneous and heterogeneous echostructures and a significant suprapatellar effusion. An ultrasound-guided biopsy confirmed the diagnosis of a recurrent diffuse TGCT complicated by vascular compression of the popliteal vein. The patient underwent mass resections, total synovectomy, and radiotherapy to reduce the risk of recurrence.  Ultrasound is cost-effective and highly beneficial for the diagnosis, treatment planning, and monitoring of diffuse TGCTs. Total synovectomy combined with radiotherapy or intra-articular yttrium-90 injection is the preferred treatment to prevent recurrence and complications.