Review Question - QID 213916

Figures A-D demonstrates localized tenosynovial giant cell tumor giant (lt-GCT), previously called giant cell tumor of tendon sheath. The same disease process can also manifest in joints of the body called diffuse tenosynovial giant cell tumor (dt-GCT), previously named pigmented villonodular synovitis.

dt-GCT is a neoplastic disease of synovial cells. It results in synovial proliferation. It is most commonly found in the knee. Patients will present with pain and swelling secondary to recurrent atraumatic hemarthroses. Xrays can show cystic erosions with sclerotic margins. MRI will show hypointensity on T1 and T2 due to hemosiderin deposits in the synovium.

Palmerini et al analyzed characteristics of 294 patients with dt-GCT. The joint most affected was the knee (60%), followed by the ankle (16%) and hip (11%). Bone involvement was present in 18%. Their recurrence rate after surgical treatment via open or arthroscopic resection was 28%, with a median time of 16 months until local recurrence. Factors associated with recurrence were larger lesions (2-5cm), male gender, diffuse pattern, and macroscopically complete resection.

Chin et al report their experience treating 40 patients with dt-GCT and who had previously undergone resection surgery. They had three treatment groups: surgery alone, surgery with intraarticular radiation therapy, and surgery with external beam radiation therapy. Their surgical synovectomy was performed through posterior and anterior approaches to the knee. Overall after treatment patients had improved Knee Society scores with 93% achieving good to excellent results and improved range of motion in all groups. They had a recurrence rate of 18%.

Figures A demonstrate soft tissue mass and erosions of adjacent bone. lt-GCT can have bony involvement in 20% of cases. Figures B and C are sagittal and axial T1 images demonstrating a hypointense mass abutting the tendon sheath. Figures D is a T2-weighted image demonstrating a hyper-intensity adjacent to the tendon sheath. Illustrations A demonstrates cystic erosions with sclerotic margins classic on Xray. Illustration B is a T2 weighted MRI with an intra-articular mass that is hypointense. Illustration C is an arthroscopic image of the synovial proliferation that is characteristic in this disease process.

Incorrect:
Answer 1: Giant cell tumor of bone is a benign aggressive tumor that predominately affects the metaphysis of long bones, most commonly around the knee. Characterized by biopsy showing multinucleated giant cells. MRI will show eccentrically located T1 hypointense lesion of the epiphysis and/or metaphysis. This is unrelated to lt-GCT.
Answer 3: Synovial sarcoma is a soft tissue sarcoma most often found in the lower extremities. They tend to present near joints. A biopsy will show spindle cells. Imaging can show intralesional calcifications, hypointensity on T1 MRI, and hyperintensity on T2 MRI. This is unrelated to lt-GCT.
Answer 4: A Baker's Cyst is a parameniscal cyst most often in the popliteal fossa between semitendinosus and the medial head of the gastrocnemius. It is an out-pouching of synovial fluid. This is unrelated to lt-GCT.
Answer 5: Synovial chondromatosis is a metaplastic disorder that can present similar to dt-GCT with knee pain and swelling, however, it is characterized by multiple intraarticular loose bodies. This is also unrelated to lt-GCT.