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http://upload.orthobullets.com/topic/8058/images/humerus xray.jpg
http://upload.orthobullets.com/topic/8058/images/mri t1 lms.jpg
http://upload.orthobullets.com/topic/8058/images/histolgy 1.jpg
http://upload.orthobullets.com/topic/8058/images/t2 mri lms.jpg
http://upload.orthobullets.com/topic/8058/images/histo 4.jpg
 
Introduction
  • Leiomyosarcoma (LMS) is an aggressive sarcoma thought to arise from the smooth muscle cells lining small blood vessels
    • it may either occur in the soft tissue (uterus) or in the bone  
  • Epidemiology
    • incidence
      • fewer than 100 case reports of extra-facial leiomyosarcoma of bone
    • demographics
      • the mean age of presentation is in 5th and 6th decades of life
    • location
      •  most frequently occurs in the metaphysis of long bones, but can occur in diaphyseal locations.
      • the most frequent sites of boney presentation are the femur, tibia, ilium, and humerus
  • Prognosis
    • LMS of bone in adults
      • 25% recurrence rate and 25% metastasis rate 
      • 75% survival at 3 years with treatment
Presentation
  • Symptoms
    • bone pain
    • palpable mass 
    • typical duration of symptoms prior to diagnosis is 6 months 
  • Physical exam
    • pelvic masses can be difficult to appreciate on inspection exam
    • can be tender or nontender to palpation
    • masses will be firm
Imaging
  • Radiographs
    • involved extremity  
      • purely osteolytic lesions with ill-distinct margins, moth-eaten, or permeative pattern of bone destruction.  
      • primarily intra-medullary but may extend into the soft tissues.  
    • chest 
      • indicated for all staging of tumors to evaluate for lung metastasis
  • CT
    • indications
      • help evaluate bone loss of involved extremity or pelvis
      • chest CT indicated in all patients as part of staging workup to evaluate for metastasis
  • MRI
    • indications
      • differentiate from benign soft tissue tumors
      • evaluate size, depth, and surrounding anatomy
    • views
      • appears dark on T1, similar to muscle tissue 
      • appears heterogeneous on T2 with areas of increased signal intensity 
      • contrast causes diffuse enhancement of signal within the lesion
Studies
  • Histology
    • a spindle cell neoplasm with similar characteristics shared between the osseous and soft tissue forms of this disease 
    • cigar-shaped nuclei
    • cells arranged into fascicles along with myofibrils running parallel 
    • presence of actin and vimentin immunoreactivity  
  • Staging
    • all tumors should be staged appropriately prior to treatment initiation
Treatment
  • Nonoperative
    • chemotherapy
      • indications
        • diffuse metastatic disease to the lungs
        • large pelvic masses with neurovascular involvement that preclude safe resection
      • outcomes
        • variable response to chemotherapy
        • better survival when chemotherapy combined with surgery than surgery alone
    • radiation
      • indications
        • controversial 
        • contaminated resection bed
      • outcomes
        • variable response, difficult to predict
  • Operative
    • early wide resection of the primary lesion and secondary reconstruction
      • indications
        • standard of care in localized disease
      • technique
        • clean margin is an important goal of surgical resection
      • chemotherapy
        • Neo-adjuvant or adjuvant  chemo/radiotherapy in the treatment of leiomyosarcoma of bone is controversial
      • radiation
        • if unable to obtain wide margin consider adjuvant radiation
 

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