Extramedullary tumors of myeloid blasts in adults as a pattern of relapse following allogeneic bone marrow transplantation

BACKGROUND. Extramedullary tumors of lymphoid and myeloid blasts outside th e well-defined sanctuaries following allogeneic bone marrow transplantation (allo-BMT) are rare. Little is known about the biology, treatment, and out come of these tumors in this setting. METHODS, In this retrospective analysis, 134 consecutive patients with acut e myeloid leukemia (AML) or chronic myeloid leukemia (CML) who underwent al lo-BMT at a single institution between 1990 and 1998 were reviewed. Five ca ses of isolated extramedullary myeloid sarcoma that occurred as patterns of recurrence following allo-BMT between 1990 and 1998 are reported. These pa tients were treated with radiotherapy, systemic chemotherapy, or a second a llo-BMT. Clinical outcome is compared with posttransplantation bone marrow relapses observed during the same period at the same institution. The liter ature on the clinical characteristics, currently available treatment, and o utcome of posttransplantation myeloid sarcoma patients was reviewed. RESULTS. Excluding isolated skin and central nervous system recurrences, th e frequency of extramedullary myeloid sarcoma encountered as a relapse patt ern following allo-BMT was determined to be 3.7% among patients with acute or chronic leukemia of myeloid origin. The survival of patients who were ma naged with radiotherapy and systemic chemotherapy was less than 1 months. A patient who underwent a second allo-BMT following local radiotherapy is al ive and in complete remission more than 33 months after the diagnosis of my eloid sarcoma. The median survival of 17 patients with posttransplantation bone marrow relapse following allo-BMT was 2.2 months. When posttransplanta tion medullary recurrences are analyzed, patients with CML had a median sur vival of 12 months, with a significantly better 5-year survival rate than p atients with AML (0 vs. 60%, P = 0.015; median survival, 12 months). CONCLUSIONS. The clinical outcomes of patients with recurrent isolated extr amedullary myeloid sarcoma following allo-BMT are poor, as in any leukemic relapse, with the exception of patients with CML in this setting. Cancer 19 99;85:608-15. (C) 1999 American Cancer Society.