Synovial Tumors 19 F.M.Vanhoenacker, J.W.M.Van Goethem, J.E.Vandevenne, M

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Chapter

Synovial Tumors 19 F.M.Vanhoenacker, J.W.M.Van Goethem, J.E.Vandevenne, M. Shahabpour

Contents tumors are classified as fibrohistiocytic tumors [3]. Therefore, these tumors are discussed more appropri- 19.1 Introduction ...... 311 ately in Chap. 14. 19.2 Benign Synovial Tumors ...... 311 Synovial sarcoma has been known for longer time as 19.2.1 Benign Cystic Lesions ...... 311 a misnomer, as it is not derived from true synovial cells. 19.2.1.1 Classification and Pathogenesis ...... 311 Actually, synovial sarcoma is regarded as a malignant 19.2.1.2 Clinical Manifestations ...... 321 19.2.1.3 Imaging ...... 321 tumor of uncertain differentiation [3]. It will be dis- 19.2.2 Giant Cell Tumors and PVNS ...... 322 cussed in Chap. 23. 19.2.3 Other Synovial Tumors and Tumor-like Lesions 322 19.2.3.1 Synovial Chondromatosis and Synovial Chondrosarcoma ...... 322 19.2 Benign Synovial Tumors 19.2.3.2 Synovial Hemangioma ...... 323 19.2.3.3 Synovial Osteochondroma ...... 323 19.2.1 Benign Cystic Lesions 19.2.3.4 Lipoma Arborescens ...... 323 19.3 Malignant Tumors Around the Joints ...... 323 There exist several types of cystic para-articular soft 19.3.1 Synovial Sarcoma ...... 323 tissue lesions, like synovial cysts, ganglion(cysts), and 19.3.2 Metastatic Spread of Cancer ...... 323 bursae. As there is much controversy in the radiological References ...... 323 literature about the nomenclature and classification of para-articular cystic lesions, we will first propose a logical classification, related to their possible pathogenesis, before discussing their appearance on imaging.

19.1 Introduction 19.2.1.1 Classification and Pathogenesis

The synovial membrane is derived from embryonic Cystic lesions can be divided into four categories, mesenchyme and lines nonarticular areas in synovial mainly based upon the combination of two criteria joints, bursae and tendon sheaths. Cells of the synovial (Table 19.1) [15, 8]: membrane regulate the exchange of substances between 1. The anatomical location and relationship with the blood and synovial fluid, and they synthesize hyal- adjacent joint, e.g., a communicating stalk with the uronate, which is a major component of the synovial joint.This communication can be visualized by imag- fluid [1]. There are considerable differences in the ap- ing or can be surgically proven. pearance of the synovial membrane, depending on local 2. The histological composition of the cyst wall and the mechanical factors and the nature of the underlying tis- contents. sue. For instance, in high-pressure joints the synovium is flat and acellular whereas in low-pressure joints it ࡯ (Arthro)synovial Cyst. The term synovial cyst de- resembles cuboidal or columnar epithelium [5]. scribes a continuation or herniation of the synovial Traditionally, discussion of synovial tumors in radio- membrane through the joint capsule. In the French lit- logical textbooks includes benign cystic synovial erature, the term “arthrosynovial” cyst is preferred, tumors, as well as giant cell tumors, PVNS and synovial which refers to their intimate relationship with the adja- sarcoma. cent joint. Indeed, there is always a communication with However, according to the latest World Health Orga- the adjacent joint, and the histological composition is nization Classification of Tumors, PVNS and giant cell identical to that of the joint cavity. It consists of a collec- 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 312

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Table 19.1. Classification of para-articular cystic lesions Communication Wall composition Cell lining Contents with joint (Arthro)synovial cyst Present Continuous mesothelial “True” synovial cells lining Mucinous fluid Ganglion (cyst) May be present Discontinuous mesothelial Flattened pseudo-synovial cells Mucinous fluid lining Bursitis de novo Absent Fibrous wall No mesothelial lining Fibrinoid necrosis Bursa (permanent) Absent Continuous mesothelial “True” synovial cells Mucoid fluid lining

a b

c d

Fig. 19.1Ia–d. Synovial cyst – Baker’s cyst in different patients: axial fat suppressed TSE T2 MR Images (c).Due to its ﬂuid content, a lateral radiograph of the left knee; b axial ultrasound of the the lesion is of high signal intensity on T2-weighted images (c,d). popliteal fossa; c axial fat suppressed turbo spin echo T2-weighted Baker’s cyst is a very common synovial cyst located in the popliteal MR image; d sagittal fat suppressed turbo spin echo T2-weighted fossa. It represents a distended bursa gastrocnemio-semimembra- MR image.Soft tissue mass in the popliteal fossa,with internal sec- nosa and is as other synovial cysts lined by a normal synovial ondary osteochondromatosis, due to longstanding degenerative membrane. It may be the result of increased intra-articular pres- joint disease (a). Anechoic structure (b) with a communicating sure in cases of substantial joint effusion. In the knee joint these stalk (arrow) towards the knee joint between the semimembra- effusions are often associated with meniscal tears, rheumatoid nosus tendon (1) and the medial gastrocnemius muscle (2). This disease, osteochondral lesions or degenerative disease typical extension towards the joint is also well appreciated on the 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 313

Chapter 19 Synovial Tumors 313

tion of synovial fluid, lined by a continuous layer of the pure (arthro)synovial cysts, which represent an ex- “true” synovial cells. The prototype is the Baker’s cyst, tension of the joint cavity outside the joint, caused by a which results from an extrusion of synovial fluid herniation through a “locus minoris resistentiae” with- through a breach between the gastrocnemius muscle in the joint capsule. This explains why the histological and semimembranosus tendon at the popliteal fossa composition of those cysts is exactly a copy of that of (Fig. 19.1). Other examples can be seen near other joints the adjacent joint, and why the cellular lining consists of (spine, shoulder, elbow, hip, hand, foot, and ankle), but a continuous layer of “true”synovial cells.As those cysts are less frequent. They are usually associated with joint grow and may extend further away from the joint into diseases, like osteoarthrosis, inflammatory and post- the soft tissues, they may undergo degenerative changes. traumatic joint diseases. The elevated intraarticular First, the cellular lining may become discontinuous and pressure, due to an accumulation of joint fluid, causes individual cells may flatten, as they may be subject to herniation of joint fluid and synovium through a “locus fluctuations in intracystic pressure. This results in para- minoris resistentiae” within the joint capsule. articular cysts, in which the wall composition consists of a discontinuous layer of pseudosynovial cells. Ulti- ࡯ Ganglion (Cyst). Ganglia also contain mucinous flu- mately, the original communication with the joint may id, but their wall consists of a (discontinuous) layer of be obliterated. Therefore, at the other end of the disease flattened pseudosynovial cells, surrounded by connec- spectrum, a ganglion cyst may represent an advanced tive tissue (pseudocapsule) [8, 10, 15, 16]. degenerative stage of a synovial cyst, in which the con- A communication with the adjacent joint is not al- tinuous synovial lining and the communication with ways present. the joint may be lost during the process of degeneration There remains much controversy in the literature (Fig. 19.2). concerning the pathogenesis of ganglion cysts. Several The following arguments support the “synovial” the- theories have been proposed, including displacement of ory in their pathogenesis: synovial tissue during embryogenesis, proliferation of 1. The similar histological composition of synovial and pluripotential mesenchymal cells, degeneration of con- ganglion cysts: both the contents (mucinous fluid), nective tissues after trauma, and migration of synovial and the cellular lining are very similar (continuous fluid into the cyst (synovial herniation theory) [9]. layer of true synovial cells in arthrosynovial cysts vs Based upon the similar appearance on imaging and a discontinuous lining of flattened pseudosynovial surgery and on the similar wall composition of synovial cells in ganglion cysts). cysts and ganglion cysts, we believe that the synovial 2. The morphology of some ganglion cysts, e.g. their herniation hypothesis is the most satisfactory. Accord- course along capsular arteries or capsular nerve ing to this theory,both synovial cysts and ganglion cysts branches, may explain a peculiar form. This is espe- are formed by a herniation of synovium through a cially true for adventitial cystic disease and perineur- breach in the adjacent articulation. Both types of para- al cysts, which can be considered as variants of gan- articular cysts are believed to be variants of the same glion cysts [7, 12, 17] (Fig. 19.3). disease spectrum. At one end of the spectrum, we have

a b c

Fig. 19.2Ia–c. Pathogenesis according to the “synovial herniation the cellular lining consists of true synovial cells; b,c ganglion cyst: hypothesis” of: a (arthro)synovial cyst: this lesion originates from during the process of degeneration, the cellular lining may change, a herniation of the synovial membrane through the joint capsule. and become discontinuous. Ultimately, the original communica- The histological composition is identical to the joint cavity, and tion with the joint may be obliterated 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 314

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Fig. 19.3. a Adventitial cystic disease. b Perineural ganglion cysts. Both may result from dissection of fluid around articular branches of arteries, veins or nerves. a shows a sagittal T1-weighted image of the knee joint, b a sagittal T1-weighted MR image. In adventitial cystic disease, the popliteal artery is encased and focally narrowed by a polylobular hypointense structure (arrow), corresponding surgically to a cyst in the adventitia of the vessel wall (a). A ganglion cyst of the proximal tibiofibular joint consists of a moniliform hypointense structure along the course of the articular branch of the deep peroneal nerve (white arrow), running to the proximal tibiofibular joint (open arrow)

Fig. 19.4Ia–e. Ruptured ganglion cyst in the lower leg of a 54-year- old man: a ultrasound; b CT after iodinated contrast injection; c axial spin echo T1-weighted MR image; d axial turbo spin echo T2-weighted MR image; e axial spin echo T1-weighted MR image after gadolinium contrast injection. Ultrasound clearly shows a multiloculated cystic lesion in the lower leg (a). The image corre- sponds perfectly with the findings on nonenhanced CT (b). The lesion is clearly delineated with sharp borders. The adjacent fibular bone is not eroded. The MRI examination (c–e) was performed two weeks later. The cyst is ruptured, and there is fluid in the inter- and intramuscular fat planes (d). There is no evidence of hemor- rhage (c). After gadolinium injection (e) enhancement is seen in the periphery of the lesion as a result of local inflammatory e changes. This may lead to confusion in the differential diagnosis against other inflammatory soft tissue changes 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 315

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3. Functional arguments – When the para-articular cyst is directly injected or after arthrography of the adjacent joint, there is often a delayed opacification of the joint or cyst re- spectively [8, 9]. – The fluctuating volume of some cysts, sometimes complicated by rupture (Fig. 19.4), argues for a communication with the adjacent joint, which acts as a reservoir of synovial fluid [8, 15].

Ganglion cysts may be located anywhere around the joints. A para-articular location in fat layers (Fig. 19.5) or muscle (Fig. 19.6) is most frequently seen. Dissection of ﬂuid around arteries or veins or nerves results in adventitial cystic disease or peri- or intraneural cysts [7, 12, 17]. A meniscal cyst (Fig. 19.7) can also be consid- Fig. 19.5. Ganglion cyst in the subcutaneous fat of the dorsum of ered as a particular form of a ganglion cyst, in which the foot, presenting as an ovoid, well demarcated anechoic lesion synovial ﬂuid is extruded through a horizontal meniscal at the metatarsophalangeal joint. There is no obvious communica- tear, resulting in an encapsulated mass around the tion with the underlying joint meniscus [13]. Other para-articular locations like in the subperiosteal area of the diaphyses of the long bones (periosteal ganglion) are rare [5, 9], while intraosseous ganglia are frequent. Examples of intra-articular locations are paralabral cyst (Figs. 19.8 and 19.9) (shoulder and hip) and cruciate ligament cysts (Fig. 19.10) [2].

Fig. 19.6. Intramuscular ganglion cyst. CT-scan of the left lower leg shows a sharply demarcated low density lesion within the medial gastrocnemius muscle 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 316

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a b

Fig. 19.7Ia–c. Meniscal cyst: a CT-scan of the knee; b,c sagittal TSE T2-weighted MR images. Multicystic lesion within the Hoffa’s fat pad (a), associated with an air-containing tear within the medial meniscus (arrow). An oblique tear within the meniscus (b), communicating with a multicystic structure at the dorsomedial c aspect of the medial meniscus (c) is better appreciated on the corresponding MR images 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 317

Chapter 19 Synovial Tumors 317

Fig. 19.8Ia,b. Ganglion cyst in the spinoglenoid notch of the structure with some internal low signal intensity septations is seen shoulder (paralabral cyst): a axial T2*-weighted image; b coronal in the spinoglenoid notch of the scapula. T2-weighted image with spectral fat saturation. A hyperintense

a b

Fig. 19.9Ia–c. Paralabral cyst of the left hip: a standard radiograph; b axial fat suppressed TSE T2-weighted MR image; c coronal fat suppressed TSE T2-weighted MR image. The standard radiography (a) reveals the presence of a sclerotic deﬁned erosion at the superolateral aspect of the left acetabulum (arrows). On axial and coronal FS TSE T2- weighted MR images, there is a multicystic structure within the acetabular labrum, extending at the lateral aspect of the left acetabulum, causing pressure erosion (b,c). Note also the presence of internal bone debris on the standard radiographs (a), which appears as hypointense dot-like structures within the labral cyst on the FS TSE T2- weighted MR images. There is bone marrow edema at the lateral aspect of the left femoral head, as well as in the acetabulum, due to pre- c existing osteoarthrosis of the hip 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 318

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c d

Fig. 19.10Ia–d. Cysts of: a,b the posterior; c,d the anterior cruciate posterior border of the posterior cruciate ligament in the first pa- ligaments in two different patients. a is a sagittal fat suppressed tient (arrows). The fibers of the anterior cruciate ligament are in- T2-weighted MR image, b an axial fat suppressed T2-weighted terspersed by linear areas of high signal intensity on T2-weighted MR image, c an axial fat suppressed TSE T2-weighted MR image MR images in the second patient (c,d). Anterior cruciate ligament and d a sagittal fat suppressed TSE T2-weighted MR image.A high (ACL) cysts may be difficult to distinguish from partial tears of the signal intensity lesion with internal septations (a,b) is seen at the ACL 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 319

Chapter 19 Synovial Tumors 319

Fig. 19.11Ia–c. Adventitious bursa due to chronic friction at the first metatarsophalangeal joint: a clinical picture; b radiograph; c ultrasound of the first metatarsophalangeal joint. Soft tissue swelling at the medial side (a,b) of a hallux valgus deformity (arrows). On ultrasound, a well demarcated hypoechoic structure is seen at the medial aspect of the first metatarsal head

࡯ Bursa De Novo (Adventitious Bursa). Inflammation ࡯ Bursa. Bursae are synovial lined structures, which of connective tissue in areas subject to chronic friction- are found in an anatomically predisposed topography. al irritation may result in fibrinoid necrosis,with forma- They contain a small amount of lubricating, mucinous tion of a bursa de novo or an adventitious bursa. This fluid and their function is to avoid friction between two consists of a cystic structure filled with cellular debris, adjacent structures. Bursitis is an inflammation of a extracellular fluid, altered ground substance, and in- bursa, usually due to chronic mechanical friction, but flammatory exudate [14]. The most common example is may be caused by an infectious or rheumatoid disease as a bursitis de novo at the medial side of the first metatar- well. Bursitis results in abnormal accumulation of fluid sophalangeal joint, due to chronic friction over a hallux within those bursae (Figs. 19.11–19.15). valgus (Fig. 19.11). 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 320

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Fig. 19.12Ia,b. Chronic frictional infrapatellar bursitis in two dif- (arrow). The internal air is due to a previous puncture (a). In the ferent patients: a axial CT scan; b sagittal fat suppressed turbo spin second patient, an ill deﬁned high signal intensity structure is seen echo T2-weighted MR image. In the ﬁrst patient, a well delineated anteriorly to the distal patellar tendon. The irregular delineation hypodense structure at the ventral aspect of the patellar tendon may be explained by repetitive friction

Fig. 19.13. Chronic frictional bursitis olecrani.Axial ultrasound at Fig. 19.14. Chronic bursitis (arrows) at the greater trochanter, the dorsal aspect of the olecranon process of the elbow reveals an presenting as a hyperintense structure on an axial T2-weighted oval structure with a thickened hypoechoic wall (w) and an ane- image. Note the associated bone marrow edema in the greater choic center. trochanter 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 321

Chapter 19 Synovial Tumors 321

Fig. 19.15. Infectious bursitis olecrani. Axial T1-weighted image Fig. 19.16. (Arthro)synovial cyst of the wrist. For superficial after intravenous gadolinium contrast administration: the bursa joints, like the wrist, ultrasound represents an efficient tool for olecrani (b) is distended with peripheral rim enhancement. There demonstrating the cystic nature, as well as the communication is associated infiltration of the subcutaneous fat (small arrows) with the underlying joint (arrows). This can be much more difficult for deeply located joints

19.2.1.2 Clinical Manifestations tendon sheath [18]. The lesion may be multiseptate and may contain some fine internal septations. US is an ac- Clinically, these cysts present as palpable soft tissue curate technique to define the cystic nature in superfi- masses. Symptoms, including local pain or limitation of cial cysts around the wrist and the hand, but it has lim- joint mobility, are usually due to mass effect on the ited ability to visualize deeper lying structures and their surrounding tissues [13], but small cysts are usually relationship with the adjacent joint. Furthermore, cysts asymptomatic. Pseudo-thrombophlebitis is a well known containing debris or hyperplastic synovium may simu- complication, due to rupture of a Baker’s cyst. late solid mass lesions on ultrasound examinations [13]. A normal bursa is not visualized on ultrasound, or is seen only as a thin hypoechoic space or sac in a typical 19.2.1.3 Imaging anatomic location.When a bursa is distended,it appears as a hypoechoic structure with well-defined margins The role of imaging is to define the cystic nature of and contents of variable echogenicity. The internal ap- those lesions, and to demonstrate a possible communi- pearance varies according to the pathology. In a simple cation with the joint (Figs. 19.16 and 19.17). This is bursitis, there may be just anechoic fluid, with or with- important for the surgeon because the resection of the out septa. In chronic bursitis due to impingement or communicating stalk with the joint is essential to avoid overuse, more frequently there is bursal wall thickening postsurgical recurrence of the cyst. (Fig. 19.13), with internal debris of variable echogenicity. The echogenic contents may even mimic a solid ࡯ Conventional Radiography. Standard radiography is mass [18]. This is especially true for a bursitis de novo nonspecific and may reveal an ill-defined or rounded, (Fig. 19.11). noncalcified soft tissue mass. Radiographs may also demonstrate signs of associated degenerative joint dis- ࡯ CT-scan. Due to its low soft-tissue contrast, CT is of ease, bone erosion (Fig. 19.9), calcification, gas, or calci- limited value in assessing soft-tissue lesions. Para-artic- fied loose bodies in a communicating cyst (Fig. 19.1) [13]. ular cysts are of lower attenuation than muscle (Fig. 19.6) and of higher attenuation than fat. Rim en- ࡯ Ultrasound. On US, synovial cysts and ganglion hancement is seen after intravenous contrast adminis- cysts appear as anechoic masses (Fig. 19.5), and may tration [13]. A possible communication with the joint is have a visible communication with a joint (Fig. 19.16) or sometimes difficult to define on axial images. 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 322

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࡯ Arthrography/Direct Cyst Puncture. Arthrography can be useful to demonstrate the communication of the cyst with the joint cavity. However, cysts may fail to fill when the communication is very narrow or when the cyst is filled with highly viscous fluid [13].Joint communication can sometimes be demonstrated on delayed images (2 h after the injection) [9].

࡯ MRI. MR imaging demonstrates the exact location and extent of the cystic lesions, and its relationship to the joint and surrounding structures (Figs. 19.1, 19.3, 19.4, 19.7–19.10, 19.12, 19.14, 19.15, 19.17). It is very accurate in depicting associated joint disorders, such as meniscal tears (associated with meniscal cysts) a (Fig. 19.7), labral tears (in case of a paralabral cyst) (Figs. 19.8, Fig. 19.9), ligamentous abnormalities or inflammatory changes [13]. Maximum Intensity Projec- tions (MIP) of 3D acquisitions with fat saturation may be helpful to demonstrate the stalk communicating with the adjacent joint. The diagnosis of a cystic mass is usually straightfor- ward by analysis of the signal intensities of the lesion. They are typically hypo- or isointense to muscle on T1- weighted images, especially if they contain protein-rich gelatinous substances, and homogeneously hyperintense on T2-weighted images. However, there are some pitfalls. Atypical cyst content due to debris or hemor- rhage may alter the imaging appearance of the cysts. b Chronic inflammation may cause marked thickening of the synovial membrane, and, therefore mimic a solid Fig. 19.17Ia,b. Uncomplicated ganglion cyst (g) of the wrist in a soft-tissue mass. A cruciate ligament ganglion may 59-year-old man: a coronal spin echo T1- weighted MR image; b coronal turbo spin echo T2-weighted MR image. Ganglion cysts demonstrate the same signal intensity as a cruciate liga- rarely communicate with the adjacent tendon sheath or joints (ar- ment tear and may simulate a false-positive diagnosis of rows). In this case of a ganglion cyst (g) at the volar aspect of the cruciate ligament tear [13]. wrist and forearm there is no associated increase in intra-articular fluid (b). The signal characteristics of ganglion cysts are usually Cystic lesions are well circumscribed, but may be lob- comparable with those of synovial cysts: bright on T2-weighted ulated, or multicystic with internal septa. Ruptured image (b) and dark on T1-weighted image (a) cysts, due to an elevated pressure are irregularly delineated, and must be differentiated from other soft tissue tumors and hemorrhagic or inflammatory lesions. After gadolinium contrast administration, subtle rim enhancement of the peripheral fibrovascular tissue in the cyst wall is seen, but there is never central enhance- 19.2.3 Other Synovial Tumors and Tumor-like Lesions ment like in other well delineated soft tissue lesions with high signal intensity on T2-weighted images, such 19.2.3.1 Synovial Chondromatosis and Synovial as myxoma, myxoid liposarcoma, hemangioma, syn- Chondrosarcoma ovial sarcoma and mucinosis [3, 16]. Synovial chondromatosis is characterized by meta- plasia of the subsynovial connective tissue with subse- 19.2.2 Giant Cell Tumors and PVNS quent cartilage formation. In rare cases there is malignant degeneration into synovial chondrosarcoma. According to the most recent WHO classification, these These entities are discussed in Chap. 21. tumors will be discussed in Chap. 14. 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 323

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19.2.3.2 Synovial Hemangioma Things to remember: 1. Cystic soft tissue lesions can be divided into four Synovial hemangioma is a separate localization of a groups (synovial cyst,ganglion cyst,bursa de novo hemangiomatous tumor. However since it is a vascular and permanent bursa), based upon the combina- and not a synovial tumor by histological criteria this tion of their anatomical location and histological entity is discussed in Chap. 16. composition. 2. The diagnosis of a cystic lesion is usually straight- forward on ultrasound and/or MR imaging. If 19.2.3.3 Synovial Osteochondroma there is any doubt, however, on the true cystic nature of the lesion,gadolinium contrast adminis- Synovial osteochondroma is a very rare cartilaginous tration should be performed to exclude a pseudo- tumor that is not connected to bone. It occurs almost cystic benign or malignant tumor. exclusively near the joints in hand and feet. It is discussed in detail in Chap. 21.

19.2.3.4 Lipoma Arborescens References

This rare tumor will be discussed in the chapter of lipo- 1. Barland P, Novokoff AB, Hamerman D (1962) Electron mi- croscopy of the human synovial membrane. J Cell Biol 14:207 matous tumors (Chap. 15). 2. Bui-Mansfield LT,Youngberg RA (1997) Intraarticular ganglia of the knee: prevalence, presentation, etiology, and manage- ment. Am J Roentgenol 168:123–127 3. Fletcher CDM, Unni KK, Mertens F (2002) Pathology and ge- 19.3 Malignant Tumors Around the Joints netics of tumours of soft tissue and bone (World Health Orga- nization Classification of Tumours). IARC Press, Lyon, France 19.3.1 Synovial Sarcoma 4. Kim MG, Kim BH, Choi JA et al. (2001) Intraarticular ganglion cysts of the knee: clinical and MR imaging features. Eur Radiol 11:834–840 As discussed earlier in the introduction of this chapter, 5. Kobayashi H, Kotoura Y,Hosono M, Tsuboyama T,Sakahara H, synovial sarcoma is a misnomer. According to the most Konishi J (1996) Periosteal ganglion of the tibia. Skelet Radiol 25:381–383 recent WHO classification (2002),this tumor will be dis- 6. Lever JD, Ford EHR (1958) Histological, histochemical and cussed in Chap. 23 (Lesions of Uncertain Differentia- electron microscopic observations on synovial membrane. tion). Anat Rec 132:525 7. Levien LJ, Benn CA (1998) Adventitial cystic disease: a unifying hypothesis. J Vasc Surg 28:193–205 8. Malghem J, Lebon C, Vandeberg B, Maldague B, Lecouvet F 19.3.2 Metastatic Spread of Cancer (2004) Les kystes mucoides atypiques.In: Laredo JD,Tomeni B, Malghem J et al. (eds) Conduite a tenir devant une image osseuse ou des parties molles d’allure tumorale. Sauramps The metastatic spread of cancer to the joint and synovi- Medical, Montpellier, pp363–376 um is one of the rarest manifestations of malignant dis- 9. Malghem J, Vande berg BC, Lebon C, Lecouvet FE, Maldague BE (1998) Ganglion cysts of the knee: articular communica- eases, and involvement of more than one joint is excep- tion revealed by delayed radiography and CT after arthrogra- tional. It is more commonly seen in patients with phy. Am J Roentgenol 170:1579–1583 leukemia and other hematologic malignancies and is 10. McCarthy CL, McNally EG (2004) The MRI appearance of cystic lesions around the knee Skelet Radiol 33:187–209 rarely reported in those with solid tumors [11]. MRI 11. Metyas SK, Lum CA, Raza AS, Vaysburd M, Forrestier DM, shows a combination of bone and joint involvement, Quismorio FP (2003) Inflammatory arthritis secondary to with nonspecific signal behavior. The diagnosis can be metastatic gastric cancer. J Rheumatol 30:2713–2715 12. Nucci F, Artico M, Santoro A, Bardella L, Delfini R, Bosco S, confirmed by joint cytology and/or synovial biopsy. Palma L (1990) Intraneural synovial cyst of the peroneal Synovial involvement of a lymphoma will be dis- nerve: report of two cases and review of the literature. Neuro- cussed in the chapter of soft tissue lymphoma (Chap. 26). surg 26:339–344 19_DeSchepper_Synovial_Tumor 15.09.2005 13:30 Uhr Seite 324

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13. Steiner E, Steinbach LS, Schnarkowski P, Tirman PF, Genant 16. Vanhoenacker FM, Van de Perre S, De Vuyst D, De Schepper HK (1996) Ganglia and cysts around joints. Radiol Clin North AM (2003) Proceeding of the meeting of The KBVR-SRBR Am 34:395–425 Osteo-articular section Brussels, June 21, 2003. Cystic lesions 14. Van Holsbeeck M, Introcaso JH (2001) Sonography of bursae. around the knee. JBR-BTR 86:302–304 In: Van Holsbeeck M, Introcaso JH (eds) Musculoskeletal 17. Vanhoenacker FM, Vandevenne JE, De Schepper AM, De Leer- ultrasound, 2nd edn. Mosby, St Louis, pp 131–169 snijder J (2000) Letter to the editor. Regarding “Adventitial cys- 15. Vandevenne JE, Vanhoenacker F, Hauben E, De Schepper AM tic disease: a unifying hypothesis”. J Vasc Surg 31:621–622 (1997) Nosologie des kystes para-articulaires. In: Bard H, 18. Wang SC, Chhem RK, Cardinal E, Cho KH (1999) Joint sono- Drapé JL, Goutallier D, Laredo JD (eds) Le genou traumatique graphy. Radiol Clin North Am 37:653–668 et dégéneratif. Sauramps Médical, Montpellier, pp 293–303