Pigmented villonodular synovitis (PVNS) is described as a benign villous or nodular proliferation of synovium. Pigmented villonodular synovitis occurs commonly in the third and fourth decades of life. Also known as diffuse tenosynovial giant cell tumor. It is characterized by the onset of monoarticular pain and swelling, the knee being the most frequently affected (80%). Tendon, bursa, or another joint can be infrequently involved. The synovial fluid is characteristically brown (old blood) or hemorrhagic, and the plain radiograph is usually normal but erosions into the bone and subchondral cyst can occur. PVNS is best diagnosed by synovial biopsy. Microscopic examination reveals a characteristic histology, including marked synovial cell hyperplasia and subsynovial invasion by masses of polygonal cells, multinucleated giant cells, and lipid-filled macrophages. Hemosiderin deposits are all around the tissue previously took for biopsy. The Hemosiderin have a characteristic appearance on magnetic resonance imaging scans, with nodular foci of decreased signal on both T1- and T2- weighted images. A synovectomy is recommended although recurrence is common.
The incidence is close to 1.8 per million.
Proliferative disorder of synovium of joint, tendon or bursa
Young adults 3rd and 4th decads
Symptoms – pain, swelling, decreased ROM
• Synovial hemangioma
• Rheumatoid arthritis
• Slow growing mass
• Insidious onset of pain
• Monoarticular process
• May be tender to palpation
• Long-standing cases there may be destruction of cartilage, secondary degenerative change and pain characteristically in diffuse PVNS.
• Local PVNS
• Sometimes pain
• More frequently present with catching, locking and instability.
• Synovial fluid aspiration is a very common way to promptly diagnose this tumor (brownish-stained bloody fluid)
• No sex predilection
• 3rd and 4th decades of life.
• Extremely rare in children.
• Localized form
• Knee (anterior compartment)
• Diffuse form (most or all of the joint synovium)
• Knee (60-80%)
• Hip (4-16 %)
Radiographs may be normal (70% of the cases)
Some cases can show erosions, and reactive sclerotic bone
A very common non pathognomonic sign in plain radiographs is the reciprocal bony erosions on opposite sides of the joint
Demonstrates a soft tissue mass
High attenuation due to the hemosiderin within the mass.
The synovial proliferation enhances following administration of contrast.
Show increased attenuation relative to muscle
Joint effusion may also be seen
MRI (Fig. 1-10)
Periarticular or synovial nodular mass with varying degrees of bone erosion.
Nodular lesion with areas of hemosiderin (low signal on all sequences
) and hemorrhage.
On fat suppress images the tumor is high signal and hemosiderine cannot be seen.
Joint effusions and bony erosions are well demonstrated. As with CT, contrast enhancement is typical.
Fig. 1-10: Magnetic Resonance of a PVNS of the knee shows a synovial mass with minimal bone erosion of the medial articular plate. On T1W and T2W images shows a tumor with low intensity areas (hemosiderin) and hemorrhage. Joint effusion is well demonstrated. Post contrast images demonstrate an irregular pattern of enhancement.
Localized (Fig. 11A)
Large and bulky
White to brown
May be yellow
Diffuse (Fig. 11B)
Larger than 5 cms
Villous pattern is lacking in extraarticular tumors.
Other possible appearance is Multinodular tumor with white, yellowish and brownish areas.
Microscopic (Fig. 12-14)
Lipid Laden Macrophages
Spindled cells (with pale cytoplasm)
Multinucleated giant cells
Prominent chronic inflammatory cells
Foams cells are observed in the periphery of the lesions.
Hemosiderin pigment prominent
Stromal and fibroblast cell proliferation
Numerous cleft-like (alveolar) spaces
Variable degree of villous, nodular and pigmentation (hemosiderin) and inflammatory components
Frondlike synovial projections
Both forms of the tumor are associated to a translocation t(1;2)(p13;q37) with a CSF-COLA3 gene fusion.
Fig. 11A: Gross pathology of a Localized PVNS demonstrates a 4x4 cs white and yellow nodular mass, without hemorrhages or necrosis.
Fig. 11B: Gross pathology of a Diffuse PVNS demonstrates a multinodular tumor with white, yellowish and brownish areas. Hemosiderin areas are easily distinguished.
Fig. 12-14: Highly cellular sheet of spindled cells, multinucleated giant cells and chronic inflammatory cells with variable degree of pigmentation (hemosiderin). Numerous cleft-like spaces or 'pseudoglandular' spaces, surrounded by xanthoma cells. Cleft-like spaces are commonly seen in diffuse-type giant cell tumors.
Can result in severe arthritis
May totally destroy the bone
Extends beyond joint into adjacent nearby tissue
Recurrence rate for local PVNS is 8% and 80 to 100% for diffuse PVNS with surgery alone.
Malignant change or varieties possible, but extremely rare.
TREATMENT (Fig. 15-18)
• Aggressive open synovectomy (Diffuse PVNS)
Fig. 15-18: Posterior approach of the knee, demonstrates the resection of PVNS from the popliteal area of the knee. Extensive dissection of the neurovascular structures was previously carried out. The PVNS was surrounding the blood vessels and nerves in the leg.
• Rarely, amputation necessary
• High recurrence rates
• More limited treatment possible (Local PVNS)
• For solitary nodules
• Arthroscopy partial synovectomy
• Radiotherapy may also be considered in conjunction with surgery
• Moderate doses may improve local control