Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Sarcoma (Epitheloid and Synovial)

Basics
Description
  • Epithelioid sarcoma:
    • A high-grade soft-tissue sarcoma that is prone to local recurrence, lymph node invasion, and pulmonary metastases.
    • Most common soft-tissue sarcoma of the upper extremity
    • Often confused with granulomatous processes
    • Occurs often in young patients (15-40 years old)
  • Synovial sarcoma:
    • A high-grade malignancy on the soft tissue
    • Occurs in para-articular regions
    • Rarely occurs inside a joint
    • Locations:
      • Lower extremity: 60%
      • Upper extremity: 25%
      • Trunk: 10%
      • Head/neck: 10%
General Prevention
No preventive means are known.
Epidemiology
No causes are known, but a genetic connection for synovial sarcoma exists.
Incidence
  • No data available for epithelioid sarcoma:
    • Young patients
    • Upper extremity
  • Synovial sarcoma:
    • Occurs in young patients: 15-40 years old
    • Male:Female ratio is 1.2:1.
Risk Factors
No risk factors are known.
Genetics
  • Epithelioid: No genetic factors are known.
  • Synovial:
    • A characteristic chromosomal abnormality is found in all cases.
    • Balanced reciprocal translocation: t(X;18) (p11.2;q11.2):
      • SYT gene on chromosome 18
      • SSX1 or SSX2 on the X chromosome
      • Gene fusion products: SYT-SSX1, SYT-SSX2
Pathophysiology
  • Epithelioid and synovial sarcoma:
    • Unregulated growth of the soft-tissue mass
    • Hematologic spread to the lungs
    • Lymphatic spread to the lymph nodes
  • Epithelioid sarcoma can arise in the superficial or deep tissues.
    • When superficial, it grows in the subcutaneous tissues as a nodule and may ulcerate through the skin.
    • In the deep tissues, it often is firmly attached to muscles, tendons, or fascial structures.
Etiology
No etiologic factors are known.
Associated Conditions
No associated conditions are known.
Diagnosis
Signs and Symptoms
  • Patients present with a soft-tissue mass.
    • Pain is present in ~50%.
    • Some patients note a long-term presence of the mass.
    • May be slow or rapid growth
History
Patients may note that the mass has been present for a short time and is growing or that it has existed for a long time with little or no growth.
Physical Exam
  • Carefully examine the extremity and note the following features of the mass:
    • Size
    • Depth: Above or below the fascia (attached to skin or deep tissues?)
    • Mobility: Fixed or movable?
  • Also note any overlying skin changes, such as erythema.
  • Check for lymphadenopathy.
Tests
Imaging studies are the main modality for defining the anatomic parameters of the mass.
Lab
No specific laboratory studies
Imaging
  • Radiography:
    • Plain films are used to evaluate the primary lesion.
    • Look for:
      • Cortical bone destruction
      • Periosteal reaction
      • In synovial sarcoma only: Mineralization within the mass (occurs in ~20% of patients)
  • MRI:
    • The most useful imaging study
    • Used to define lesion’s size, depth, and relationship to important structures such as nerves and blood vessels
  • CT:
    • Used to look for pulmonary metastases and lymphadenopathy
    • Chest in all patients
    • Pelvis/abdomen, axilla to evaluate lymph node chains from the primary site
Diagnostic Procedures/Surgery
  • Needle biopsy is necessary to differentiate synovial sarcoma from other sarcomas and the many benign causes of soft-tissue tumors.
  • Because of the propensity for lymph node involvement, sentinel-node biopsy sometimes is necessary.
Pathological Findings
  • Characteristic morphologic findings for epithelioid sarcoma:
    • Nodular growth pattern
    • Central necrosis
    • Epithelial appearance of the cells
  • For synovial sarcoma, several types (listed in order of occurrence):
    • Biphasic (epithelial and fibrous cells)
    • Monophasic fibrous
    • Poorly differentiated
    • Monophasic epithelial
Differential Diagnosis
  • Soft-tissue masses have a long list of benign and malignant differential diagnoses.
  • Epithelioid sarcoma can be confused with a number of entities, both clinically and pathologically:
    • Granuloma annulare
    • Rheumatoid nodule
    • Squamous cell carcinoma
    • Necrotizing infectious granuloma
    • Necrobiosis lipoidica
Treatment
Special Therapy
Radiotherapy
  • Virtually all patients are treated with a combination of wide surgical resection and radiation therapy.
  • Radiation therapy can be delivered in a number of different ways:
    • Preoperative external beam
    • Postoperative external beam
    • Brachytherapy tubes
Physical Therapy
Physical therapy often is used after surgery to regain ROM and strength.
Medication
  • Chemotherapy often is used to reduce the risk of pulmonary metastases.
    • Multiagent intensive therapy
Surgery
  • Wide surgical resection with as large a margin as possible is the cornerstone of treatment and necessary to reduce the risk of local recurrence.
    • Lymph node dissection is necessary if abnormal nodes are found on physical examination or after imaging.
    • Limb preservation in >90% of patients
    • Amputation occasionally is necessary.
      • Involvement of major nerves and blood vessels
      • Inability to remove the entire tumor with negative margins
Follow-up
  • Patients are followed at close intervals to monitor for pulmonary metastases and local recurrence.
    • CT of the chest every 3-4 months for 2-3 years, then every 6 months until 5 years posttreatment, and then annually thereafter
    • MRI with contrast of the limb every 6 months for 2-3 years to monitor for local recurrence
Disposition
  • Patients with epithelioid and synovial sarcoma should be referred to a multidisciplinary team:
    • Orthopedic oncologist
    • Radiation oncologist
    • Medical oncologist
    • Plastic surgeon
Prognosis
  • The prognosis for epithelioid sarcoma is fair with adequate local control.
    • ~40-50% disease-free survival
    • Metastases to lymph nodes, lungs, and other soft-tissue sites
  • Poor prognostic findings:
    • Male gender
    • Nondistal extremity tumors
    • Size >5 cm
    • Increased tumor depth
    • High mitotic index
    • Necrosis
    • Vascular invasion
    • Inadequate initial excision
  • The prognosis for synovial sarcoma is excellent if local control can be achieved and pulmonary metastases do not develop.
    • 5-year survival rates have been reported to be 50-80%.
    • Favorable variables:
      • Age <25 years
      • Size <5 cm
      • Absence of poorly differentiated areas
    • Unfavorable variables:
      • Age >40 years
      • Size >5 cm
      • Poorly differentiated areas
Complications
  • The major complications of surgery and irradiation are:
    • Delayed wound healing
    • Arthrofibrosis (stiffness in joints)
    • Infection
Patient Monitoring
Patients are followed closely after surgery to monitor wound healing, ROM, local recurrence, and pulmonary metastases.
Miscellaneous
Codes
ICD9-CM
171.___Neoplasm, malignant, connective tissue
Patient Teaching
  • Patients must be taught the essential features of this tumor and the principles of treatment.
    • Wide surgical resection is necessary.
    • Irradiation often is necessary to reduce the risk of local recurrence.
    • Careful monitoring with imaging studies and physical examination is necessary after surgery.
Activity
Unrestricted activity after full wound healing
Prevention
No preventive methods
FAQ
Q: Is surgery necessary for all patients?
A. Surgery with as wide a margin as possible is necessary to reduce the risk of local recurrence.
Q: What is the risk of pulmonary metastases?
A: Metastasis to the lungs occurs in ~50% of patients.
Q: How often can the limb be saved?
A: Limb preservation can be achieved in ~90% of patients.
Q: Is chemotherapy necessary for all patients?
A: Patients at high risk for pulmonary metastases, especially those with large tumors (>10 cm), should consider chemotherapy.

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