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http://upload.orthobullets.com/topic/8052/images/Case B - axilla - xray - parsons_moved.jpg
http://upload.orthobullets.com/topic/8052/images/Case B - axilla - MRI - parsons_moved.jpg
http://upload.orthobullets.com/topic/8052/images/Histology C - parsons_moved.jpg
http://upload.orthobullets.com/topic/8052/images/Case C - leg -ct - parsons_moved.jpg
http://upload.orthobullets.com/topic/8052/images/Histology A_moved.jpg
http://upload.orthobullets.com/topic/8052/images/Histology B - Parsons_moved.png

Introduction
  • Malignant soft tissue sarcoma which arises near joints, but rarely within the joint
    • cellular origin of synovial sarcoma is unknown, but it is not the synovial cell or any cell involved in the synovium
      • the name synovial sarcoma is a misnomer.
  • Epidemiology  
    • demographics
      • most common sarcoma found in young adults (15-40 years) 
      • affects more males than females
    • location
      • it is the most common malignant sarcoma of the foot 
  • Genetics
    • chromosomal translocation t(X;18) is observed in more than 90% of cases   
    • translocation forms the SYT-SSX1, 2, or 4 fusion protein  
      • SYT-SSX4 is rare
 
SYT-SSX1
SYT-SSX2
Frequency More common (60% of tumors Less common (40% of tumors)
Histology type
Biphasic
Monophasic
Gender
M:F = 1:1
M:F = 1:2
Presentation Larger, with metastases Smaller, without metastases
Survival Worse Better
 

  • Metastases
    • synovial sarcoma typically shows high histologic grade
    • metastasis may develop in 30-60% of patients
      • like other sarcomas, the lung is most common site of metastasis 
      • synovial sarcoma is one of the rare soft tissue sarcomas which can metastasize to lymph nodes 
        • the other sarcomas which can metastasize to lymph nodes include, epitheliod sarcoma, angiosarcoma, rhabdomyosarcoma, clear cell sarcoma
        • can stage with lymph node biopsy
          • while lymph node metastasis is a poor prognostic sign, it is not as bad as lung metastasis
    • metastasis is more common with large, deep, and high grade sarcomas
  • Prognosis
    • overall prognosis is poor
      • 5 year survival is approximately 50%
      • 10 year survival is approximately 25%
    • SYT-SSX fusion type is most important prognostic factor
      • SYT-SSX2 better survival
Presentation
  • Symptoms
    • typically present as a growing mass in proximity to a joint
    • may be painless or painful
    • most commonly occur in periarticular locations
      • knee, shoulder, elbow, foot
      • 60% are found in the lower extremity
  • Physical exam
    • examine for regional lymphadenopathy
Imaging
  • Radiographs
    • can show soft tissue mineralization (calcification) in these tumors 
    • may resemble heterotopic ossification
  • CT
    • can show calcification in the soft tissue mass 
  • MRI
    • MRI reveals a heterogenous mass that is typically dark on T1 weighted images and bright on T2 weighted images
Histology
  • Characteristic findings 
    • classical synovial sarcoma shows a biphasic appearance with two typical cell types
      • spindle cells (fibrous type of cells) 
        • relatively small and uniform and found in sheets of malignant appearing cells with minimal cytoplasm and dark atypical nuclei
      • epithelial cells 
        • gland, nest, or cyst like cells    
    • rarely, synovial sarcoma can also present with poorly differentiated or monophasic fibrous cell histology, consisting only of sheets of spindle cells
    • cellular origin of synovial sarcoma is unknown, but it is not the synovial cell or any cell involved in the synovium.  The name SYNOVIAL sarcoma is a misnomer  
  • Immunostaining for   
    • synovial sarcoma stains positive for 
      • vimentin 
      • epithelial membrane antigen
      • sporadic S-100 
      • epithelial cells stain positive for keratin
Treatment
  • Operative
    • wide surgical resection with adjuvant radiotherapy
      • indications
        • standard of care in most patients
      • technique
        • radiotherapy
          • may be delivered either pre-surgery or post-surgery
        • chemotherapy
          • data regarding chemotherapy in synovial sarcoma suggests that chemotherapy may improve both local control and overall survival
IBank
  Location
Xray
Xray
CT
B. Scan
MRI
MRI
Histo(1)
Case A
pelvis
 
 
 
Case B
axilla
 
 
 
Case C
leg
 
 
 
 
Case D
             
(1) - histology does not always correspond to clinical case 


 

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