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Pigmented Villonodular Synovitis

*Dr. Bhavuk Garg, #Dr. Rajesh Malhotra, жDr Surya Bhan

*Postgraduate, Department of Orthopaedics, All India institute of medical sciences, New Delhi.
#Additional Professor, Department of orthopaedics, All India institute of medical sciences, New Delhi.
жProfessor, Department of orthopaedics, All India institute of medical sciences, New Delhi, India.

Address for Correspondence:
Dr. Bhavuk Garg,
Postgraduate, Department of Orthopaedics, All India institute of medical sciences, New Delhi, India


J.Orthopaedics 2005;2(4)e4


Pigmented villonodular synovitis is an uncommon disease characterized by hyperplastic synovium, large effusions and bone erosions. The disease was first described by Jaffe et al. as a distinct entity in 1941.1 Pigmented villonodular synovitis (PVNS) is a locally aggressive benign tumor that arises from the synovial tissue. Another variant, giant cell tumor of tendon sheath is a similar synovial tumor that occurs in tendon sheaths. In the original description of the disease, the term "pigmented villonodular synovitis" was applied to a lesion that occurred in the synovial membrane of joints and tendon sheaths and was characterized by fibrous stroma, hemosiderin deposition, histiocytic infiltrate and giant cells.1 Subsequently, two forms of the disease were identified: a localized subtype characterized by a pedunculated lesion and a subtype with diffuse joint involvement.2


The exact cause of PVNS remains controversial 2-6. It doesn't seem to run in families. It doesn't seem to be caused by certain jobs or activities. Some people with PVNS remember that they hurt their joints at some time. Several theories are based on the histological appearance and cellular components of the lesion. The theories regarding cause include:

(1) Localized lipid metabolic derangement
(2) Repeated nontraumatic inflammation
(3) A benign neoplastic process
(4) A response to blood or blood products within the joint.

The most widely held theory is that the disease is an inflammatory reaction of the synovium.1, 2 However, some evidence exists that it is a benign neoplastic process.5


The incidence of pigmented villonodular synovitis is 1.8 cases per 1 million people per year, with no environmental, genetic, ethnic or occupational predilection.7 Most studies show equal prevalence in males and females, although some investigations report a slightly greater predilection in males.7 The localized form of the disease usually has a female predominance. PVNS is rare in children and affects mostly young adults. It has the highest prevalence during the third and fourth decades, however, it has been found in patients as young as 11 years and as old as 70 years.8

Clinical features

PVNS is considered locally aggressive because it may invade the adjacent bones, although this usually does not happen, except when the affected joint is the hip. It usually does not spread beyond the affected area. The vast majority of patients with pigmented villonodular synovitis have monoarticular complaints of pain and swelling. Polyarticular involvement is rare. In both the localized and diffuse subtypes, the knee is the most commonly affected joint (about 80 percent of patients) 3. The hip joint is the second most common location, followed by the small joints of the hand, foot, temporomandibular joint, ankle or elbow. The presentations of the disease in the knee and hip are somewhat different. The localized form in hand occurs most commonly in the fingers, in particular, the volar aspect of the first 3 fingers, and is the most common soft tissue tumor of the hand.

Clinical features depend on the size and location of the tumor. Symptoms may include

  • Swelling of a joint (usually painless)

  • Joint effusion (fluid, usually bloody), in the joint

  • Pain (sometimes).

Sometimes limping or difficulty in using legs, arms, hands or feet

Patient may have a "popping" sensation while moving the joint. The symptoms usually start slowly and may come and go over time. Patients with hip involvement occasionally report episodes of extreme pain, which may represent hemorrhage into the joint space. During these exacerbations, patients may be able to relieve the pain by positioning their hip in a flexed and externally rotated position. This positional relief of pain is typical of a joint effusion or inflammatory process of the synovium, in that the repositioning minimizes pressure within the joint.

Physical examination reveals one or more palpable nodules or diffuse joint swelling. Swelling may feel warm and be somewhat tender to palpation. Up to 96 percent of patients with knee involvement have distention of the suprapatellar pouch and a large effusion.4 As many as 40 percent of patients have a diffuse palpable synovial mass.4 Patients also have a slightly decreased ability to flex and extend the joint. Up to 90 percent of patients complain of mild to moderate tenderness, mainly over the medial patellofemoral area.4 In addition, arthrocentesis yields blood-tinged synovial fluid in 44 to 69 percent of patients.4, 7

Differential Diagnosis

Pigmented villonodular synovitis remains a diagnostic challenge. On average, the disease is not correctly identified until 4.4 years after presentation9.  The difficulty stems from the insidious onset and nonspecific presentation of the disease, as well as its subtle radiographic findings. Pigmented villonodular synovitis should be considered in the differential diagnosis of patients from 20 to 45 years of age who have monoarticular symptoms (Table 1). Diffuse pigmented villonodular synovitis of the knee can also mimic extensor mechanism malalignment (patellofemoral syndrome), ligament instability and meniscal lesion.4



Differential Diagnosis
Inflammatory arthritis
Rheumatoid arthritis
Psoriatic arthritis
Systemic lupus erythematosus
Septic arthritis
Synovial chondromatosis
Pigmented villonodular synovitis
Benign or malignant bone tumor
Avascular necrosis (hip only)


X-rays: The radiological appearance of PVNS depends on the location. A nodule in the hand may have soft tissue swelling and bone erosion on plain x-ray. In patients with pigmented villonodular synovitis of the knee, plain radiographs often appear normal. However, radiographic findings in diffuse disease (Fig1) can include a periarticular soft tissue density (in up to 80 percent of patients), expansion of the suprapatellar pouch and local osseous changes mainly confined to the patellofemoral articulation10. The changes at the patellofemoral joint result from abnormal patellar tracking because of the synovial mass lifting and stretching the extensor mechanism, thereby allowing shear forces to act on the articular cartilage. Osteopenia is occasionally found, and degenerative changes may be detected in 30 to 40 percent of patients.10 In general, bone and joint changes are less common in the knee than in the hip, because of the ability of the knee capsule to expand to accommodate the hyperplastic synovium. Bone erosion or cysts will be present in tighter joints like the hip, elbow, ankle or wrist. Calcifications are not a usual feature of PVNS. Rarely, a focus of dystrophic calcification may be seen in an area of PVNS.  In pigmented villonodular synovitis of the hip, radiographs show bony erosions in the head and neck of the femur and acetabulum in 95 percent of patients.3 These erosions are found early in the course of hip disease and appear as cyst like structures on anteroposterior radiographs. An average of three to four erosions, ranging from a few millimeters to 5 cm in diameter, is typically seen3. A thin sclerotic rim may also be present and is due to the slow growth of the process. In the late stages of the disease, the articular joint space decreases, most often superolaterally, in 70 to 75 percent of patients3. Plain radiographs cannot confidently exclude effusion as a cause for symptoms, nor can it help determine the extent of disease.

Arthrography: Radiographic contrast may be injected into the joint following joint aspiration. With contrast filling of the joint, findings demonstrate multiple irregular nodular-filling defects of variable sizes, which produce the typical cobblestone appearance of the synovium seen on arthrography.

Bone scan: Technetium-99m etidronate bone scanning may show diffuse mild uptake when bone erosions are present. However, the study may reveal no findings when the disease is confined to the synovium. Thus, a normal bone scan does not exclude the diagnosis of pigmented villonodular synovitis.

Computed tomography: CT scan is able to pick up the hemosiderin and demonstrates the extent of the synovial involvement as well as bone erosion and cysts. CT imaging is useful for needle biopsy guidance when a histological diagnosis is required. CT is hobbled by its inability to completely show the extent of disease and other pathology around or within the joint.

Magnetic resonance imaging: MRI is highly sensitive and specific for the diagnosis of pigmented villonodular synovitis. Characteristic MRI findings (Fig3) include joint effusion, lifting of the joint capsule, low signal intensity on both T1- and T2-weighted images (because of hemosiderin deposition), hyperplastic synovium (that appears as a lobulated synovial mass), bony erosions and preservation of bone density.9, 11, 12 Hyperplastic and hypervascular synovium enhances following intravascular administration of gadolinium chelates. MRI findings are not pathognomonic for PVNS, and similar findings may be seen in rheumatoid arthritis, hemophilic arthropathy, amyloid arthropathy, synovial osteochondromatosis, and degenerative joint disease. Differentiating calcifications from hemosiderin-laden foci in the setting of PVNS may be difficult, and plain films should be used in this setting to confirm or deny the presence of calcifications.

A combination of plain films and MRI should be used in preoperative evaluation of a patient with PVNS. This combination yields an accurate diagnosis and maps out the extent of disease for the surgeon prior to treatment.


Gross pathologic features include thickened synovium, with a combination of villous and nodular proliferation depending on the site of involvement. Two types of villi are present in the diffuse form of PVNS, including coarse villi with a "shag carpet" appearance and fine or fernlike villi. The nodular component is seen predominantly in tendinous or extra-articular lesions. The nodules are well demarcated and may be sessile or pedunculated, although they lack a true capsule. Bony invasion through the joint capsule is possible.

The diagnosis of pigmented villonodular synovitis is confirmed by biopsy of the synovium. On microscopy, PVNS is characterized by the presence of hemosiderin-laden multinucleated giant cells. In addition, lipid-laden macrophages, fibroblasts, and other large polyhedral-shaped mononuclear cells are present, have abundant cytoplasm, and possess oval nuclei. Hemosiderin also is found within the surrounding tissues (fig4). The ubiquitous presence of hemosiderin lends the tissue the characteristic pigmented appearance. The lesions tend to be hypervascular and demonstrate synovial hyperplasia. The location of the polyhedral cells below the synovial membrane suggests that perhaps the cell of origin is a fibrohistiocyte. The pathologic differential includes hemosiderotic synovitis, rheumatoid arthritis and synovial chondromatosis. A characteristic finding of PVNS is the invasion of the subchondral bone with resultant cyst formation.


The exact treatment for PVNS varies from patient to patient, usually depending on

  • Patientís  age, overall health, and medical history

  • Extent of the disease and whether it is causing pain

  • Whether the tumor has invaded the bone

  • Patientís tolerance for specific medications, procedures, or therapies

  • Patientís preference

Treatment options are:

Synovectomy: As PVNS can continue to grow and invade the bone, the treatment of choice is usually an operation called a synovectomy14, in which the affected synovial tissue is surgically removed. Any associated bony lesions should be carefully curettaged and bone grafting should be done, if needed. Total synovectomy (open or arthroscopic) is required for the diffuse form while local excision may be sufficient for the nodular form. Arthroscopic synovectomy may be indicated for nodular form or for inactive form of diffuse disease. Open synovectomy is the treatment of choice for patients with active form of diffuse disease. There is a high rate of recurrence, particularly for diffuse form, after synovectomy is performed. If it does recur it usually causes minimal symptoms, including chronic swelling.

Radiotherapy: Radiotherapy can be considered in patients with previous adequate resection of disease who experience local relapse and in patients with a large amount of disease in whom complete resection is not possible.15It has been used in the management of recurrences with varying success. However it is generally avoided in children because of growth issues and the concern about radiation associated malignancy later in life. In one retrospective series, 15 13 of 14 patients with recurrent or extensive diffuse disease treated with radiation therapy were disease-free at a mean follow-up period of 69 months. Eleven patients were characterized as having good or excellent limb function, and three patients had fair function

Combination therapy: - In the report by 13Blanco et al, the authors presented the results of combined partial arthroscopic synovectomy and low-dose radiation therapy (RT) in the treatment of diffuse PVNS of the knee. The authors conducted a prospective study of the treatment of 22 patients with clinical, ultrasonic, and histologically confirmed findings of diffuse PVNS of the knee. Their protocol included anterior (patellofemoral, medial, and lateral) arthroscopic synovectomy and postoperative RT with a total dose of 2,600 cGy. Combination therapy was effective in reducing symptoms of pain and edema, and in improving overall function of patients. Nineteen patients (86%) had good or excellent results at an average follow-up of 33 months (range, 26 to 76 months); 3 had clinically and ultrasonographically confirmed recurrence of disease and were treated with repeat arthroscopic synovectomy without harmful effects from RT.

Radiation synovectomy/radiosynoviorthesis (RS): It means radionuclide therapy of joint synovitis or synovial processes by intra-articular injection of  90Y silicate/citrate or 186 Re sulphide or 169 Er citrate. 90 Y colloids are suitable for the knee joint only. 186 Re sulphur colloid is suitable for hip, shoulder, elbow, wrist, ankle and subtalar joints. 169 Er citrate colloid is suitable for metacarpophalangeal, metatarsophalangeal and digital interphalangeal joints. The reported success rate is 60-80%. Complications specific to it are temporary increase in synovitis and late radionecrosis.

TNF-blockade therapy: Recently TNF-blockade with infliximab has been reported as an effective therapy for refractory pigmented villonodular synovitis.17

Joint reconstruction: The bone destruction caused by PVNS may be extensive.  Synovectomy may not relieve all symptoms in patients with significant destructive changes in the joint. In these situations, arthrodesis or total joint replacement should be considered. Posterior stabilized prosthesis is recommended in order to maximize the exposure as well as the open synovectomy. If PVNS is seen as an incidental finding, it should not affect the decision to proceed with a preplanned reconstructive procedure. A series of 11 patients with active diffuse pigmented villonodular synovitis of the knee treated with synovectomy and total knee arthroplasty showed a local control rate of approximately 70 percent and good to excellent joint function at a mean follow-up period of 10.8 years.16

The long-term outlook for a patient with PVNS varies from patient to patient depending on:

  • the extent of the disease

  • the size and location of the tumor

  • the tumor's response to therapy

  • the age and overall health of patient.

 Generally, PVNS has a good prognosis because it is usually not considered an aggressive tumor.


1) Jaffe HL, Lichtenstein L, Sutro CJ. Pigmented villonodular synovitis, bursitis, and tenosynovitis. Arch Pathol 1941;31:731-65.
2) Granowitz SP, D'Antonio J, Mankin HL. The pathogenesis and long-term end results of pigmented villonodular synovitis. Clin Orthop 1976;114:335-51.
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6) Singh R, Grewal DS, Chakravarti RN. Experimental production of pigmented villonodular synovitis in the knee and ankle joints of rhesus monkeys. J Pathol 1969;98:137-42.
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9) Cotten A, Flipo RM, Chastanet P, Desvigne-Noulet MC, Duquesnoy B, Delcambre B. Pigmented villonodular synovitis of the hip: review of radiographic features in 58 patients. Skeletal Radiol 1995;24:1-6.
10) Flandry F, McCann SB, Hughston JC, Kurtz DM. Roentgenographic findings in pigmented villonodular synovitis of the knee. Clin Orthop 1989;247:208-19.
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12) Eustace S, Harrison M, Srinivasen U, Stack J. Magnetic resonance imaging in pigmented villonodular synovitis. Can Assoc Radiol J 1994;45:283-6.
13)  Blanco CE, Leon HO, Guthrie TB. Combined partial arthroscopic synovectomy and radiation therapy for diffuse pigmented villonodular synovitis of the knee.   Arthroscopy 2001 May;17(5):527-31
14)  DJ Ogilvie Harris et al. Pigmented villonodular synovitis of the knee: the results of arthroscopic synovectomy, partial synovectomy, and arthroscopic local excision. JBJS. Vol 74-A. 1992. 119-123.
15) O'Sullivan B, Cummings B, Catton C, Bell R, Davis A, Fornasier V, et al. Outcome following radiation treatment for high-risk pigmented villonodular synovitis. Int J Radiat Oncol Biol Phys 1995;32:777-86.
16) Hamlin BR, Duffy GP, Trousdale RT, Morrey BF. Total knee arthroplasty in patients who have pigmented villonodular synovitis. J Bone Joint Surg [Am] 1998;80:76-82
17) E-J A Kroot et al. Tumour necrosis factor {alpha}blockade in treatment resistant pigmented villonodular synovitis. Annals of the Rheumatic Diseases 2005;64:497-499


 This is a peer reviewed paper 

Please cite as :Vaibhav Bagaria:Bone Morphogenic protein: Current state of field and the road ahead.

J.Orthopaedics 2005;2(4)e3





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