Radiologic spectrum of extramedullary relapse of myelogenous leukemia in adults.

OBJECTIVE: Chloroma, also know as granulocytic sarcoma, is a localized extramedullary tumor composed of malignant cells of the myeloid cell line. It occurs most frequently secondary to a history of myelogenous leukemia as extramedullary relapse. New treatment regimens, including allogeneic stem cell transplantation, extensive use of donor lymphocyte infusion, and second transplantation, are associated with increased rates of chloroma of up to 21%. The purpose of this article is to highlight the sites of involvement as well as the morphologic and imaging features of chloroma in patients with myelogenous leukemia. CONCLUSION: Allogeneic stem cell transplantation now represents the treatment of choice for leukemia and for patients with leukemia relapse. Therefore, the rate of chloroma is likely to increase. Because clinical and laboratory data are frequently not indicative, radiologic diagnosis of chloroma will become more important.