Synovial Sarcoma

 

Bakers Cyst MRISynovial Sarcoma Foot MRI0001SS elbow 1

 

Epidemiology

 

Aggressive malignancy with high recurrence and metastatic potential

 

5 - 10% sarcoma

 

Occurs younger

- peak age 3rd-4th decade

- same age group as other synovial pathology (primary synovial chondromatosis and PVNS)

- 2nd most common in children after rhabdomyosarcoma

 

Characteristic translocation in >95% cases - t(X:18)

 

Location

 

Occur near to but rarely within joint

- extremities particularly around the knee

- most common sarcoma of the foot

 

Can be slow growing compared to other sarcomas

 

X-ray

 

May have calcification

 

Differential soft tissue lump with calcification

 

Soft tissue sarcoma

Benign soft tissue tumour - hemangioma / AVM

Myositis Ossification

 

MRI

 

Heterogenous mass, low signal intensity T1, high signal intensity T2

- may have characteristic triple signal intensity

- area hyperintensity, isointensity and hypointensity

 

Knee

 

Heterogenous mass, not communicating with joint

 

DDx Baker's cyst

- semimembranosus

- communicates with joint

- between semimebranosus tendon and medial head gastrocnemius

 

Bakers Cyst MRIBakers Cyst MRI

 

Foot

 

Synovial Sarcoma Foot MRI0001Synovial Sarcoma Foot MRI0002

 

Elbow

 

SS elbow 1SS Elbow 2SS Elbow

 

Synovial sarcoma elbow 2Synovial sarc elbow 1

 

Buttock

 

SS buttock 1SS buttock 2

 

Management

 

Up to 50% present after unplanned excision

 

Wide resection + radiotherapy

 

Chemotherapy

- of benefit in children

- may be of benefit in adults

 

Prognosis

 

Sultan et al Cancer 2009

- 1268 cases of synovial sarcoma

- 5 year survival for adults 62%

- 5 year survival for children 83%