Dr. Kevin Yip

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

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Desmoid Tumor (Extra-Abdominal)

Basics
Description
  • A common benign soft-tissue tumor that occurs in young patients
  • Although this tumor never metastasizes, a high rate of local recurrence occurs in the following locations:
    • Neck: 8%
    • Shoulder: 22%
    • Upper arm: 6%
    • Chest wall/back: 17%
    • Buttock/hip: 6%
    • Thigh: 12%
    • Knee: 7%
    • Lower leg: 5%
  • Synonyms: Desmoid tumor; Extra-abdominal fibromatosis; Well-differentiated fibrosarcoma; fibromatosis
General Prevention
No preventive measures
 
Incidence
3-4 per 1,000,000 in the United States
 
Risk Factors
Trauma (possible, but not definitely proven)
 
Genetics
No genetic factors are known.
 
Pathophysiology
Unknown (may be associated with trauma)
 
Associated Conditions
May be associated with trauma
 
Diagnosis
Signs and Symptoms
Usually a nonpainful or moderately painful soft-tissue mass
 
History
Patients may report a history of a slowly growing soft-tissue mass
 
Physical Exam
Palpate for a hard and usually fixed soft-tissue mass.
 
Tests
Imaging is the major testing modality.
 
Lab
No pertinent laboratory tests
 
Imaging
  • Plain radiographs and MRI scans should be obtained.
  • Radiography:
    • Inspect plain films for cortical erosion or periosteal reaction.
  • MRI:
    • Shows anatomic features of the tumor:
      • T1-weighted images: Low signal, excellent anatomic detail
      • T2-weighted images: Moderate to high signal with low signal areas
Diagnostic Procedures/Surgery
Diagnosis can be established only by needle or open biopsy.
 
Pathological Findings
  • Mature fibroblasts with large amounts of collagen:
    • No cellular atypia
    • Few if any mitoses
    • No herringbone pattern
    • Highly infiltrative to muscle and other soft tissues
Differential Diagnosis
  • Must differentiate from soft-tissue sarcomas and benign reactive conditions
    • May be confused with fibrosarcoma
    • May be confused with posttraumatic conditions, nodular fasciitis
Treatment
Nursing
Reassure the patient and family that the process is completely benign.
 
Radiotherapy
  • Commonly used for recurrent or unresectable tumors
    • 5200 cGy over 5 weeks with 5-10-cm margins
Special Therapy
Physical Therapy
Often used to gain ROM and strength after surgical excision
 
Medication (Drugs)
  • Because of the high recurrence rate, many different medication regimens have been tried, with variable results, but none of these measures have been definitely shown to be effective.
  • 3 therapies generally are used for patients with recurrent tumors:
    • Low-dose chemotherapy (vincristine/methotrexate)
    • Tamoxifen
    • NSAIDs
Surgery
  • Wide surgical resection with negative margins is the preferred modality.
    • Often difficult to achieve secondary to the invasive nature of the tumor
Follow-up
  • Patients are followed every 6-12 months:
    • MRI with contrast is the best modality.
Issues for Referral
Patients should be referred to an orthopaedic oncologist.
 
Prognosis
  • The prognosis is excellent with regard to survival, but the local recurrence rate is very high.
    • Rarely will a patient die from this tumor.
    • Local recurrence rate is >50%.
Complications
  • The major complication is local recurrence.
  • Delayed wound healing occurs after wide resection.
Patient Monitoring
Patients are followed every 6 months with MRI scans.
 
Miscellaneous
Codes
ICD9-CM
215.__Neoplasm, benign, connective tissue
 
Patient Teaching
  • Patients are taught the major features of this tumor.
    • The tumor never metastasizes.
    • Local recurrence rate is high.
    • Important to regain ROM and strength after surgery
Activity
Patients may return to full activity after wound healing.
 
Prevention
No preventive measures
 
FAQ
Q: Do desmoid tumors ever spread to other parts of the body?
A: Desmoid tumors never metastasize. However, they may threaten a patient’s life through invasive local growth.
 
Q: What is the best way to treat recurrent tumors?
A: Recurrence is a very difficult problem. Patients often are treated with a combination of repeat surgery and irradation.
 
Q: Can the desmoid tumor be diagnosed without a biopsy?
A: The diagnosis of this tumor cannot be made without a needle or open biopsy.

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