• Pigmented villonodular synovitis (PVNS) is a slow growing lesion of uncertain etiology arising from the synovial membrane, characterized by villous and nodular overgrowths of the synovial membrane of the bursa or the tendon sheath.
• The appendicular skeleton, especially large joints such as the knee and hip joints are frequently involved.
Synonyms: Until Jaffe in 1941 proposed the term pigmented villonodular synovitis this condition has been known as synovial xanthoma, synovial endothelioma/ fibroendothelioma, Benign fibrous histiocytoma, xanthomatous GCT, Myeloplaxoma, fibrohemosideric sarcoma , Sarcoma fusigigantocellulare.
• 1852: 1st described as neoplastic process due to unrelenting growth pattern, by Chassaignac, eroding surrounding bone and joint tissue, & high recurrence rate post-resection.
• 1865: Simon described a focal form of PVNS
• 1909: Moser described a diffuse PVNS
• 1941: 1st reported & coined by Jaffe et al. as synovitis, shifting from neoplastic to inflammatory foci.
• Age: 3rd-4th decades of life, rare in children
• Sex: no sex based predilection
• Incidence: 1.8 per million population
• no predilection for any laterality
• repetitive trauma (50%) causing recurrent local hemorrhage to affected joint (cf:hemophilics show progressive erosive arthropathies).
• proliferation of the synovium of joints, tendon sheaths or bursae.
• It is a reactive condition, and not a true neoplasm.
• PVNS classically presents as a monoarticular disease, mimicking arthritis.
• Recurrent atraumatic haemarthrosis is a characteristic feature.
• Often aggressive, with marked extra-articular extension.
Monoarticular involvement (most common), occurs in two forms: localized and diffuse.
Two variants as described by Granowitz -
a. Localized form (LPVNS): focal involvement of the synovium
- Nodular / Sessile or Pedunculated masses.
- Hands & feet
b. Diffuse form (DPVNS) (more common): affects virtually the entire synovium, eg.
- Intra-articular PVNS tends to be of the diffuse form.
- Tendon sheath PVNS (Giant cell tumour of tendon sheath[GCCTS]), the nodular form.
• MC site: knee joint, followed by the hip and shoulder.
- anterior compartment common
- mostly at meniscocapsular junction
- synovium in the region of the anterior horn of the medial meniscus is the most common site
- infrapatellar fat pad, suprapatellar pouch, intercondylar notch, anterior horn of the lateral meniscus, and the medial and lateral recesses of the knee have been reported.
• Uncommon : elbow, ankle, shoulder, foot, wrist
• Rare : spine, cervical involvement commoner than thoracic and lumbar
o Pain (80%)
o Reduced range of movement(52%)
o Instability/palpable mass(12%)
Type specific features:
- if untreated, causes continuous pain and discomfort, limiting ADLs
- at knee often present with signs and symptoms of meniscal pathology (locking, catching, and instability)
- episodic character of joint effusion—the patient may have completely symptom-free periods between exacerbations
- Slow, insidious onset of pain, swelling, and
- stiffness in the involved joint
- most or all joints involved
- swelling and pain more pronounced
- decreased range of motion of the affected joint
- poorly localized
- with sometimes extra-articular extension, either primary or recurrent.
- may encroach on major neurovascular structures.
- Osteoarthritis- continued inflammation and joint erosions lead to articular cartilage destruction, may finally need total joint arthroplasty.
Aspiration of joint: characteristically reveals a blood tinged brownish-stained aspirate.
• Soft tissue swelling will be marked due to haemorrhage and lobulated synovial tissue.
• May reveal cysts or erosions in the joint mimicking gout.
• Bony erosions are usually from without, especially in the hip
• periarticular erosions, with a thin rim of reactive bone
• Osteoporosis is characteristically absent
• Can affect the epiphysis
• Reciprocal bony lesions on opposite sides of the joint, despite articular preservation, are highly suggestive of PVNS
• Late feature of joint space narrowing indicates articular cartilage loss, is difficult to distinguish from primary OA.
• ideal investigation
• nodular mass (periarticular or synovial) with bone erosion
• MRI is invaluable in early diagnosis and evaluating extent. Nodular synovial masses -low signal on T1/T2 sequences
• “dark on dark” on T1- and T2-weighted images
• Loculated joint effusions, Complex heterogeneous echogenic masses and markedly thickened synovium
• direct visualisation of synovium
• Has both diagnostic and therapeutic value in resection of tumours
• Normal arthroscopic findings however does not exclude PVNS (Klompmaker et al)
• Synovium looks like a “shaggy carpet”.
• LPVNS is pedunculated, lobular lesion localized to one area of the synovium.
• On microscopy, Histiocytes, lipid laden macrophages, hemosiderin containing cells and frequent giant cells are seen.
• Subsynovial nodular proliferation of large round, polyhedral or spindle cells with prominent cytoplasm and pale nuclei.
• Hemophiliac lobular synovitis (↑hemosiderin deposition, lacks lipidladen histiocytes and giant cells, which is classic indications of PVNS)
• Rheumatoid arthritis,
• Meniscal tear, or other ligamentous injury
o Total synovectomy (open or arthroscopic):
- Open (anterior approach midline incision or medial parapatellar arthrotomy) for the diffuse form for the intraarticular component
- Arthroscopic synovectomy, has gained popularity, has several advantages over the open technique, preferred for LPVNS, shows higher recurrence in DPVNS.
- The standard anterior portals are not effective, whereas the accessory posterior portals are necessary
to accomplish total posterior synovectomy
o Vascular or neurologic injury may occur during this procedure, especially if there is posterior extra-articular
extension of the lesion or fibrosis after irradiation. Open synovectomy should be preferred in such cases
o Open posterior synovectomy (“lazy S-shaped” incision): done subsequently for extensions into the popliteal fossa.
• Local excision: for the nodular form (recurrence rare).
• Radiotherapy (3500- 4000 cGy) (Radiation induced synovectomy/ intra-articular radiation synovectomy using yttrium Y-90) has been used in the management of recurrences with varying success; side effect is soft tissue radionecrosis
• Advanced cases with secondary arthritis should be addressed with arthroplasty plus extensive synovectomy to decrease recurrence.
• LPVNS: excellent prognosis, low recurrence rate if managed surgically, recurrence 8%.
• DPVNS: surgical excision difficult, recurrence rate of up to 46%.
• The debate continutes: malignant or inflammatory-
- Rare reports describe malignant transformation and metastasis, (presence of trisomy 7 and clonal DNA rearrangements reported).
- Bertoni et al reported eight patients with malignant PVNS; mortality rate was 50%.
- Oehler et al found strong support for its being a chronic inflammatory process and not noeplastic.
- Currently, data are inconclusive to prove PVNS as either malignant or inflammatory process.
- It shows neither cellular atypia nor abnormal mitosis, recent cytogenetic studies say that pathogenesis remains unresolved.
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 Relat Res 1976;114:335–51.
3. Oehler S, Fassbender HG, Neureiter D, Meyer-Scholten C, Kirchner T, Aigner T: Cell populations involved in pigmented villonodular synovitis of the knee. J Rheumatol 2000;27: 463-470.
4. Bertoni F, Unni KK, Beabout JW, Sim FH: Malignant giant cell tumor of the tendon sheaths and joints (malignant
pigmented villonodular synovitis). Am J Surg Pathol 1997;21:153-163.