A CLONAL TRANSLOCATION T(10-21) IN AN OPTIC GLIOMA OF A PATIENT WITH NEUROFIBROMATOSIS TYPE-1 (NF1)

An 11-year-old boy affected by neurofibromatosis type 1 is presented w ith severely impaired vision on the right eye (0.1). MRI demonstrated a 2.3 x 1.8 cm tumour of the optic chiasma. After open biopsy cytogene tic analysis was performed on primary cultures of this optic glioma (g rade I). A clonal translocation t(10;21)(q 21.2;21.1) was detected in 66% of the metaphases analysed. The boy received fractioned irradiatio n with a total tumour dose of 60 Gy. The ultimate MRI taken 18 month a fter radiotherapy showed no residual tumour. The vision on the right i mproved to 0.2, but decreased on the left to 0.6. The patient attends high school with no impairment in his daily life.