Granulocytic sarcoma of the base of the skull in chronic myeloid leukemia

: A 54 years old patient with Ph' negative chronic granulocytic leukaemia is reported, who presented rapidly progressive multiple cranial nerve palsies. A cerebral CT scan showed an invasive tumoral disease on the base of skull. Histologic examination of this mass was diagnostic for granulocytic sarcoma, which was the presentation form of an extramedullary blastic crisis. The general characteristics of granulocytic sarcoma are commented, special attention being paid to its appearance in the course of chronic granulocytic leukaemia.