Long-term remission with imatinib mesylate in Philadelphia chromosome-positive AML presenting as primary extramedullary myeloid sarcoma.

In this case report, we describe the first account in the literature of a patient who presented with extramedullary myeloid sarcomas (EMS) and Ph+ AML without leukemic manifestations. EMS are rare, destructive, extramedullary tumor masses that consist of immature leukemia cells. These tumors can occur anywhere in the body and have to be differentiated from lymphoma, carcinoma or infectious processes. We report a previously healthy 61-year-old male who presented with progressive left-sided hip pain. Magnetic resonance imaging (MRI) of the left hip joint revealed an extensive lytic lesion with pathological fracture of the femur. The lesion was confirmed by biopsy to be EMS with bcr-abl rearrangement in tumor cell nuclei by fluorescence in situ hybridization (FISH). Laboratory tests showed normal metabolic and complete blood counts with normal differential. Peripheral blood RT-PCR for bcr-abl was negative. Bone marrow examination revealed a normocellular with progressive trilineage hematopoiesis and no evidence of increased blast count. On the basis of available literature for the treatment of EMS, our patient received standard AML induction chemotherapy consisting of idarabucin and cytarabine. After cytogenetics studies of the bone marrow revealed bcr-abl rearrangement, we discontinued further chemotherapy and managed the patient with imatinib mesylate 400mg p.o.q. day. Follow-up at time of manuscript preparation, the patient remains in complete cytogenetic remission (CCR) for 22 months. To the best of our knowledge, this is the first case report of Ph+ AML presenting as a primary EMS without leukemic manifestations.