1. MUSCULOSKELETAL : MK 14
PIGMENTED VILLONODULAR SYNOVITIS: MAGNETIC RESONANCE IMAGING APPEARENCE
A.B Abdallah, K.Mrad Dali, F.Bouzayène, K.Kadri, N.Mama, M.Ben Maitigue*, K.Tlili
Radiology service, Sahloul Hospital
*Orthopaedic surgery service, Sahloul Hospital
MK14

2. INTRODUCTION Pigmented villonodular synovitis (PVNS) is a rare
benign proliferative disorder primarily occurring in the large joints of the appendicular skeleton such as the knee and hip joints.
PVNS is potentially aggressive lesion that attacks the synovium of joints, tendon sheaths or bursae
Diagnosis is made on clinical features, aspiration of the joint, radiographic features and magnetic resonance imaging (MRI), which is the most useful.

3. OBJECTIVES
To evaluate the magnetic resonance (MR) imaging of pigmented villonodular synovitis (PVNS) of the big joints.

4. MATERIALS AND METHODS
A retrospective review of MR imaging of big joints was performed in 12 patients with clinical and histologically confirmed PVNS
PVNS was diagnosed by synovectomy in 7 cases and arthroscopy in 5 cases.

5. RESULTS There were 5 males and 7 females
A mean age of 33 years at diagnosis
All lesions presented as a solitary intraarticular mass
In 9 cases, the disease was located in the knee
It involved the ankle in 2 cases and the hip in 1case.
Clinical symptoms varied gratly (table)
Radiographs revealed a normal appearance in 6 cases, a focal soft tissue mass in 5 cases, bone erosions in 1 case.

6. Reuslts
Articular ultrasonagraphy showed heterogenous echogenic masses in 2 cases and a markedly nodular thickened hypoechoic synovium in 2 cases
MRI showed in all cases a joint effusion and nodular thickened synovial membrane with prominent T1 low signal intensity, variable T2 signal intensity and “blooming” artifact from hemosiderin (seen with gradient-echo sequences).

7. MRI Patients Sex/age Localisation Clinic Radio-graphy Ultra- sound
Thickened synovial
Joint effusion
bone T1 T2
T2*
Gado
M/45Y
right knee
-pain
normal -
low
hemosiderin +
F/12Y
Right knee
-Hemarthrosis
-swelling
F/53Y
-Pain, swelling
-hemarthrosis
Erosion bone
Soft tissu mass
high
M/22Y
-Pain
Femoral erosion
F/45Y
femoral erosion
M/53Y
Left knee
M/19Y
nodular thickened hypoechoic synovium
F/42Y
M/34Y
Normal
F/39Y
right ankle
heterogenous echogenic masse
F/19Y
Right ankle _
F/8Y
Right hip

8. Case1: A 19 years old girl with pain aind swelling right knee
DP FATSAT
Radiography(a) is normal
MRI: -joint effusion (*)
- synovial thickening prominent in the anterior portion of the joint (arrows)
DP FATSAT

9. c d Case 1 T2* a b T1+C T2 FATSAT
*Mild blooming artifactis seen on the gradient-echo image (a,c) (arrowheads)
*Sagittal T1&T2-weighted postcontrast show prominent diffuse enhancement (arrows) and joint effusion (*). d
T1+C

10. Case2: A 53years old woman with reccurent hemathrosis and swelling right knee.
DP FATSAT
T2 STIR
MRI reveal a large amount of high-signal-intensity tissue (*) with posterior extension that replaces the entire knee joint. Extrinsic erosions of the
femur and tibia with low-signal-intensity margins are also seen (straight arrows).
Radiography shows extensive erosion of the femoral lower extremity with sclerotic margins (arrows) and maintained knee joint space.

11. Case 2 T2* T1+C b a c T1+C: coronal
(a) The gradient-echo image also shows focal hypointense areas (arrowheads), findings that represent the blooming artifact from hemosiderin
The tissue mass (*), has prominent diffuse enhancement on axial(b) and sagittal (c)- T1-weighted postcontrast c
T1+C: coronal

12. Case 3: a 19 year old teenager with a swelling left knee
(a) Lateral radiograph
shows an illdefined
area of softtissue
opacity that
replaces the normal
Hoffa fat pad (arrow). a T2 T1
(b)Transverse sonogram of the knee reveals the hypoechoic intraarticular softtissue
mass (arrows)
Sagittal T1& T2-weighted: reveal an effusion and synovial
thickening in the anterior portion of the joint(*) b

13. Sagittal T1-weighted postcontrast shows prominent diffuse enhancement
Case 3
T2*
Mild blooming artifact is seen on the gradient-echo image
T1 FATSAT+C
DP FATSAT
Sagittal proton-density–weighted fatsuppressed: There is a thick low-signal-intensity rim with areas of nodularity
Sagittal T1-weighted postcontrast shows prominent diffuse enhancement

14. Cas 4: A 39 years old woman had pain and swelling in the anterior aspect of his ankle for four years. T2 a T1
-(a)Lateral radiograph of the ankle shows an anterior soft-tissue mass (curved arrows)
-MRI shows a well-defined localized mass in the anterolateral ankle joint (*) which has an intermediate density T1 & T2 signal with prominent diffuse enhancement (arrowheads).
T2*

15. Case 4
STIR
T1+C
T1+C
The anterior soft-tissue mass presents a mildly high STIR signal with prominent diffuse
enhancement (arrowheads) on sagittal and axial sequences.

16. Cas 5: A 19 years old girl who presents ankle pain and swelling.
*Lateral radiograph: anterior soft-tissu mass of the ankle joint
*This mass presents with an intermediate T1& T2 signal without bone erosion.

17. T2*
T1+C
STIR
The anterior soft-tissue mass presents a mildly high STIR signal with prominent diffuse enhancement (*) on sagittal and axial sequences.
The gradient-echo image shows focal hypointense areas (arrowheads), that represent the blooming artifact from hemosiderin .
T1+C

18. DISCUSSION
Pigmented villonodular synovitis (PVNS) is a slow growing lesion of uncertain etiology arising from the synovial membrane.
It is a disease of synovial membrane characterized by a proliferation of mononuclear cells, probably of histiocytic origin, deep to the synovial lining cells.
It represents a benign, hypertrophic synovial process characterized by villous, nodular, and villonodular proliferation and pigmentation from hemosiderin of the synovial membrane of the bursa or the tendon sheath.

19. Patients present with joint pain, swelling, and stiffness.
Discussion
Pigmented villonodular synovitis most commonly affects adult patients in the third of fourth decades of life, in our study 4 patients (33 %) were aged under 22 years
Patients present with joint pain, swelling, and stiffness.
Although any joint may be affected by PVNS, the knee is the most common site, involved in 80 % of cases ( 75%) in our study. Other joints frequently involved are the hip, shoulder, and ankle.
These lesions are subclassified as localized or diffuse form.

20. Usually only one joint is affected
Discussion
Usually only one joint is affected
Because clinical signs and symptoms are typically nonspecific and laboratory tests are unremarkable, the radiologist plays a key role in the diagnosis and treatment of this pathology.

21. Radiography
Radiographic findings are normal in up to 20% of cases. It was normal in 50% in our study.
Overall, osseous abnormalities are present in 15%– 25% of cases
Extrinsic erosion, often with well-defined sclerotic margins, of the underlying bone is the most common osseous abnormality, seen in 9%–25% of cases. It involves joints with tight capsules, because of pressure phenomenon (foot or ankle).

22. Periosteal reaction (8% of cases) and calcifications (6%) are rare
Radiography
Subtle or obvious juxtaarticular soft-tissue masses that appear dense because of high iron content (hemosiderin) in the synovium
Periosteal reaction (8% of cases) and calcifications (6%) are rare
Preservation of bone density.

23. Sonographic appearances
Sonographic appearances of intraarticular PVNS are nonspecific.
Sonographic features of diffuse intraarticular disease include joint effusion, comple heterogeneous echogenic masses, and markedly thickened hypoechoic synovium that may have nodular and villous projections
Extrinsic erosion of underlying bone may also be seen.

24. Sonography
PVNTS manifests as a hypoechoic solid mass with well-defined margins that is intimately related to the associated involved tendon
Doppler imaging commonly reveals increased blood flow in all types of PVNS.

25. CT
PVNS lesions may show high attenuation because of the presence of hemosiderin.
It can also be caused by chronic bleeding or calcifications.
CT is useful indelineating bone cyst formation and erosions.
CT is well suited for Imaging guidance of diagnostic core needle biobsy.

26. MR Imaging
MR imaging has become the technique of choice for diagnosis and follow-up in patients with pigmented villonodular synovitis.
It is useful for preoperative, non-invasive diagnosis of PVNS in many cases
The appearance depends on the relative proportions of lipid, hemosiderin, fibrous, stroma, pannus, fluid and cellular elements

27. MR Imaging
The most characteristic finding is nodular intraarticular masses of low signal intensity on T1 (all patients), T2 (75% in our study) and proton density.
Areas of low signal intensity on T2-weighted images are due to the magnetic susceptibility effect produced by hemosiderin and are more manifest in the periphery of the lesions, present in all our cases.
This decreased signal intensity is more pronounced on gradient-echo images and at high field strengths.

28. MR Imaging
Gradient-echo images demonstrate an enlargement of the low-signal-intensity areas (“blooming”) that is caused by magnetic susceptibility artifact.
The blooming effect, which specifically signifies the presence of hemosiderin as the cause of low signal intensity, is nearly pathognomonic of PVNS at MR imaging.

29. MR Imaging
Occasionally, intralesional areas of high signal intensity on both pulse sequences may be present. These areas are believed to be due to fat, edema, or inflammation,
PVNS lesions characteristically show prominent contrast enhancement with the administration of gadolinium (90% in our study),
The signal intensity of the lytic subchondral lesions varies and may indicate the presence of fluid, soft tissue, or hemosiderin.

30. Treatment
Treatment of PVNS is required to prevent progressive loss of function and destruction of the involved joint or the tendon or bursa
Treatment options include surgical resection, radiation therapy, pharmaceutical modulation of the disease, or a combination of these approaches
Synovectomy may be performed with either an arthroscopic or open arthrotomy technique
The recurrence rate for localized disease is generally lower (from 0% to 44% )than that for diffuse intraarticular PVNS (8% to 56%).

31. Conclusion
PVNS represents an uncommon benign hyperthrophic synovial process
It is characterized by villous, nodular, and villonodular proliferation and pigmentation from hemosiderin
The MR imaging is useful for diagnosis and is optimal for identifying the extent of synovial disease, surveying and detecting reccurence.