1. Rhabdomyosarcoma Masquerade Syndrome LC Clarke, RS Thampy, R Ajit, L Irion, R Bonshek, S Ataullah, B Leatherbarrow Manchester Royal Eye Hospital

2. Rhabdomyosarcoma Most common primary orbital malignancy of childhood. Presenting signs may mislead the unsuspecting clinician We present a series of five consecutive patients referred to Manchester Royal Eye Hospital over the course of the last 2 years, each with a different initial diagnosis. We highlight how rhabdomyosarcoma may mimic other orbital disorders, leading to a potentially life threatening delay in appropriate management.

4. Occurs at sites of embryonic tissue fusion Head,neck, midline Classification related to prognosis Botyroid and spindle: Best Embryonal : intermediate Alveolar and pleomorphic :poor

5. Features of Striated muscle differentiation Bright cytoplasmic eosionophilia +/- cross striations Immuno Panel; – MyoD1(nuclear staining) – Desmin – Myogenin and myoglobin

6. Case 1 FP – age 9 years. 2 week hx of right inferior fornix lesion “Conjunctival papilloma”

7. CT orbit Axial View with contrast Lesion at right medial canthus

8. H & E Spindle to round, pleomorphic tumour cells Immunohistochemical analysis

9. a)Squamous papilloma-like appearance of at the time of biopsy. b)Histology showing round and spindle-shaped cells with mitoses. c) Demonstration of cell positivity for desmin. d) (d) Conjunctival squamous papilloma.

10. Local recurrence following chemotherapy 2 years prior. Orbital exenteration, further chemo & radiotherapy Recurrence in exenterated orbit RIP 2010 (6 years post presentation)

11. Case 2 LB – age 10 years. 4 week hx of swelling right eye “Orbital cellulitis”

12. CT orbit Axial View with contrast CT - Upper lid local disease

13. H & E H&E – Diffuse infiltration by poorly differentiated tumour cells

14. Surgical debulking &chemotherapy - good response

15. Case 3 LR – age 10 years. 1 week hx of right proptosis and diplopia. “Langerhans cell histiocytosis”

16. MRI Orbit Axial MRI - Mass in lateral orbital wall and temporal fossa

17. H & E Diffuse infiltration by poorly differentiated tumour cells

18. Bone marrow mets. Chemo and radiotherapy – ongoing Lagophthalmos. Persistent ocular surface problems

19. Case 4 JB – age 5 years. 2 month hx of progressive right ptosis “Upper lid chalazion”

20. CT Orbits Axial View CT - Upper lid local disease

21. H&E Alveolar rhabdomyosarcoma. Clear cell component to the right

22. Surgical debulking &chemotherapy - good response

23. Case 5 LG – age 11 years. 3 week hx of right upper lid swelling “Eyelid papilloma”

24. CT Orbits Axial View CT - Thickening of upper lid & regional lymphadenopathy

25. H&E H&E – Area of alveolar architecture. Note stretched surface epithelium.

26. Surgical debulk, chemo and radiotherapy

27. A high index of suspicion Following treatment, local tumor recurrence occurs in 18% of cases, metastasis in 6%, and death in 3%. – paediatric patient – history of rapidly progressive orbital, eyelid or conjunctival lesion.

28. The diagnosis of rhabdomyosarcoma should considered until proven otherwise – to avoid unnecessary delays in diagnosis – expedite appropriate management, – optimize the outcome for this group of patients.