[Two cases of orbital embryonal rhabdomyosarcoma with chromosome aberration]

Two cases of pediatric orbital rhabdomyosarcoma leading to visual dysfunction with rapid growth.

A two-year-old girl who presented with eyelid edema. MRI revealed a tumor in the orbit. The tumor grew rapidly resulting in eye ball displacement and corneal epithelium disorder, and was subsequently removed. Histopathological examination revealed randomly proliferating cells shaped from small round to spindle cells positive for myogenin, desmin and HHF 35 in immunohistochemistry. Based on histopathology and clinical examination, diagnosis of embryonal rhabdomyosarcoma was made. A nine-year-old boy presented with eyelid edema. MRI revealed a tumor under the skin of the upper palpebra extending to the orbit. The tumor grew rapidly to the extent that the eyelids could not be opened spontaneously. Hisitopathologically, spindle-shaped cells were detected proliferating randomly in myxomatous stroma, positive for myogenin and desmin in immunohistochemistry. Based on histopathology and clinical examination, diagnosis of embryonal rhabdomyosarcoma was made. Genetic analysis depicted aberration of chromosome 7 in the first case and tetraploidy in the second case. Both patients subsequently underwent chemotherapy and local radiotherapy and no recurrence has been detected over 1 year.

Although rhabdomyosarcoma of the orbit often progresses rapidly and may cause visual disturbances, favorable outcome can be expected by proper management especially in cases with certain histopathological types. A comprehensive approach will be required to elucidate the pathogenesis of orbital rhabdomyosarcoma and genetic abnormalities.