Aleukemic bcr-abl positive granulocytic sarcoma

Granulocytic sarcoma (GS) can occur de novo or in association with intramedullary myeloid disorders. With the advent of sophisticated molecular detection techniques to detect diagnostic genes such as bcr-abl, PML-RARA and CBFB/MYH11 in bone marrow or peripheral blood, many cases of the so called 'primary' GS are questionable. We report a case of primary GS where the tumor mass bcr-abl translocation was demonstrated by fluorescent in situ hybridization in which there was no evidence of chronic myeloid leukemia (CML). This is an important finding as it highlights the possibility that CML may present as a sole extramedullary form, and illustrates potential treatment by tyrosine kinase inhibitor.