Twenty-six patients with inv(16)(p13q22) or del(16)(q22) in association with acute myelomonocytic leukemia (AMML-M4, FAB classification), and abnormal marrow eosinophils have been treated at this institute. Initial bone marrow eosinophilia (greater than or equal to 4%) was observed in 22 of 26 patients (85%), and abnormal eosinophil morphology, characterized by immature cells with some interspersed basophilic granules, was evident in 26 of 26 (100%). Giemsa-banded chromosome analysis performed in all patients revealed 16 cases with inv(16)(p13q22) alone, and ten cases with additional chromosome changes. Twenty-five patients received combination induction chemotherapy, and 23 (92%) achieved complete remission (CR). The median duration of remission was 18 months (range, six to 72 + months), and the median duration of survival was 34 months (range, 0.5 to 133 months). Nine patients (35%) relapsed in the CNS at a median time of 19 months (range, six to 133 months) from first marrow CR. All patients had leptomeningeal disease, and in addition, six of nine (66%) demonstrated two or more enhancing lesions on computed tomography brain scan, consistent with intracerebral myeloblastomas. Review of 384 Giemsa-banded patients with acute myeloid leukemia revealed no other morphologic or cytogenetic subgroup with either an equivalent incidence of CNS leukemia or documented intracerebral myeloblastomas. This series of inv(16)(p13q22)/del(16)(q22) AMML reports a favorable prognosis for such patients and associates a specific clonal cytogenetic subgroup of acute leukemia with a distinct propensity for CNS relapse, manifesting as leptomeningeal disease and intracerebral myeloblastomas.

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Primary malignant lymphoma of the central nervous system (CNS) is rare and only infrequently involves the spinal cord, usually in association with multifocal CNS spread. We report a case of primary lymphoma infiltrating lumbar nerve roots without evidence of systemic lymphoma. There has been an excellent response to combined modality therapy, comprising radiotherapy with intrathecal and intravenous cytotoxics. The patient remains well and active 22 months after diagnosis. The literature regarding these rare tumors is reviewed.

Ten patients with acute myelomonocytic leukemia (AMML) and inversion of chromosome 16 who had CNS involvement were identified at M.D. Anderson Hospital between January 1972 and December 1984. The nervous system signs and symptoms were evaluated in detail. CT scans, CSF cytologies, and treatment modalities were reviewed. Two patients underwent biopsies of lesions that proved to be granulocytic sarcomas. AMML with inversion 16 carries a much higher (33%) incidence of CNS involvement in the form of leptomeningeal metastasis and/or granulocytic sarcoma than all other acute nonlymphocytic leukemias (5%). The reason for this appears to be related to the chromosomal aberration and not to prolonged survival.

2 patients with hairy cell leukemia (HCL) complicated by multiple cutaneous and other malignancies are described. The second malignancies behaved in a much more aggressive fashion than would be expected in an immunocompetent population, and were lethal in both patients. The literature regarding second malignancies in immune compromised patients, and in HCL in particular, is reviewed.