Abstract
Purpose :
Orbital Rhabdomyosarcoma is highly malignant tumor predominantlyaffecting children mostly in the first decade.Opthalmologist are the first to face this life threatening disease,thus prompt diagnosis by them for further lifesaving treatment is essential.
Methods :
A retrospective study of all the cases with confirmed tissue diagnosis of rhabdomyosarcoma at KKESH since 1985,The chart review included thier demographic ,clinical features with clinical ,radiological and hisopathological correlation,DNA was extracted from parraffin embedded biopsies using DNeasy blood and tissue extraction kit.Genotyping was performed at KFSH&RC to detect chromosomal abnormality and copy number variations regionsthat might have caused the development of this tumor.
Results :
18 males (62.8)and 8females were included with mean age at presentation of 6.9 years SD of 4.4.88.5% were Saudi.The right side was more affected (61.50%).Proptosis and globe displacment was were the most common clinical presentatios.Family history of malignancy was positive in 7.7% only.Embryonal histopathological subtype was the commonest in 19 cases (73.1%)and was observed to present in younger age group with significant predominance of superior orbital involvement (p=0.024).In all cases tissue diagnosis was confirmed by at least one of the known diagnostic IHC stains.Radiologically,Using MRI with its superior soft tissue contrast and multiplanar capability the embryonal type showed insignificant higher ADC value(1.17)compared to alveolar type(1.10)with the mean ADC of 0.67-0.09x10-3mm2/S(p=0.98).
Genetic profiling showed copy number gain in regions spanning PAX3,DDIT3,Gli,Wnt6 genes.DICER1 gene implification was found in 9 sporadic cases with no positive family history of hereditary carcinoma.
Conclusions :
Orbital rhabdomyosarcom is most common primary orbital malignant tumors with mean age of 7 years and predominance among males.
Histopathologically the embryonal type is the most commonest and it is significantly correlated with superior orbital involvment.
Radiologically,Rhabdomyosarcoma shows and ADC of 0.67-0.09x10-3mm2/S(p=0.98).
The gain in PAX3,DDIT3,Gli,Wnt6 genes is new unique finding that should be studied further.Also the DICER1 gene implification is an interesting finding in the absence of familial hereditary carcinoma.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.