[Burkitt's acute lymphoblastic leukemia. Incidence and cytogenetic aspects].

We report 4 cases of patients, 5, 16, 31 and 55 years old respectively, with Burkitt type ALL. Three of them presented with a hypoaesthesia of the chin tip. The cytological features of abnormal cells were those of L3 subgroup in the FAB classification; they expressed surface immunoglobulin markers. EBV serology was positive in two cases but the titres did not indicate a recent infection. The translocation t(8;14) (q24;q32) was found in all 4 patients. In one case, it was possible to characterize a clone with a 7 neochromosome (7p+) and a clone with a supernumerary 7 isochromosome i(7q)+; in other respects these two clones showed the translocation t(8;14) and only the latter remained in the terminal phase. In these 4 patients the disease progressed dramatically even when haematological remission was obtained (two cases), predominantly due to early neuro-meningeal involvement.