Introduction
A malignant soft tissue, that was believed to originate from primitive mesenchymal tissue.
- Most common primary orbital malignancy in children, but that being said, is still very rare.
- 10% of paediatric embryonal sarcomas occur in orbit
- Soft-tissue tumour composed of mesenchymal cells that normally form striated muscle.
- Grows rapidly with ~70% during the 1st decade; average age ~6-7 years.
- Affects M:F in 3:2
Dead Giveaways
Diagnostic Tools:
Can be identified with CT and MRI
MRI scan of the rhabdomyosarcoma. Ocular displacement is evident. On T1, tumour is hypointense compared with orbital fat, iso to EOM. On T2, tumours are hyperintense to both orbital fat and EOM (as seem). 
Shows the growing tumour in proximity to extraocular muscles. Evidently, the lesion is heterogenous and isodense to the EOMs. The tumours typically are homogenous and well-circumscribed. They typically present near the extraocular muscles from the orbital soft tissues.
From the eyewiki. Shows different round and spindle cells that are at different stages of differentiation. Cells with highly eosinophilic cytoplasm and hyper chromatic nuclei.
diagnostic features
Signs:
Ptosis (sometimes palpable mass)
Proptosis
Blepharoptosis
Conjunctival and eyelid swelling
Pain may appear
Swelling and injection
May mimic inflammation
Treatment:
Radiotherapy and chemotherapy
Exenteration for resistant or recurrent tumours