We report on two cases of patients who developed diabetes insipidus (DI) before acute erythroleukaemia (EL). A brain MRI showed an empty sella turcica in one case and hypothalamo-hypophyseal peduncle damage in the second case. Reduced levels of TGF-beta1 and Vitamin D3, with associated EVI-1 over-expression and karyotypic abnormalities were documented. These two cases show specific chromosomal/molecular alterations in EL with DI. The hypothesis of pituitary involvement in erythroleukemogenesis is discussed.