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Saturday, October 13, 2012

Orbital Rhabdomyosarcoma

9 years boy
C/o
Proptosis left eye - 3 months
Drooping of left upper eye lid - 2 months
On Examination
         Left ptosis with proptosis
         Fundii normal
         EOM - restricted in superior & lateral direction [left eye]
         Va – Normal
         Vf – Normal in right eye
Pre Op CT Scan

Pre Op MRI

Pre Op MRI

OPERATIVE PROCEDURE:
Left frontal trephine craniotomy, extradural superior orbital approach and microsurgical excision of tumor.
FINDINGS:
Extraconal well defined, non-encapsulated, soft, mild vascular, whitish grey tumor attached to levator muscle.
Complete excision done
Post Op
Left ptosis
Decreased proptosis
Left superior rectus paresis
Subconjuctival hemorrhage
Histopathology


  • Rhabdomyosarcoma - Most common pediatric soft tissue sarcomas  (approximately 50%)
  • Peak age 2- 5 years
  • Male preponderance (1.4:1)
Epidemiology
  • 1/3rd  of RMS patients have other congenital abnormalities
    • GI, GU, CV, CNS
  • Majority cases sporadic; but some associated with genetic conditions
    • Li Fraumeni (p53 mutation)
    • NF 1
    • Beckwith - Wiedemann
Pattern of spread
  • Locally invasive tumor often with pseudocapsule
  • Potential for local spread along fascial or muscle planes, lymphatic extension and hematogenous dissemination
  • Regional lymphatic & hematogenous metastases -15%
Prognostic Factors
  • Histology
  • Stage
    • Primary site (most important)
    • Tumor Size
    • LN involvement
    • Metastatic disease
  • Group
    • Extent of resection
  • Age
    • < 1
    • >10
    • Skull base erosion, CN palsy & Intracranial extension
Histology
  • Gross disease
    • Soft, fleshy tumors with variation in extent of invasion and necrosis
  • IHC stains to ascertain muscle of origin
    • Antidesmin, antivimentin,  anti-muscle specific actin
    • Anti-Myo D
  • Embryonal
    • Most common
    • 60-70% of all childhood RMS
  • Boytroid
  • Spindle cell
  • Alveolar
  • Undifferentiated/pleomorphic
Histology and Survival

Clinical presentation
  • Asymptomatic mass
  • Rapid growing painless mass
  • Mass effect on associated organs and tissues
  • Commonest site orbit > parameningeal sites > other sites
Staging System
Intergroup Rhabdomyosarcoma Study Clinical Grouping Classification




Prognostic Factors
         Orbit
§  favorable prognostic site
§  lymphatic extension/hematogenous metastasis is rare
§  embryonal histology

Management
    • Surgical procedure either excision/biopsy
    • Chemo-radiation
    • Cure rates of  > 90%