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

• 1/3^rd  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%