Purpose Central nervous system (CNS) involvement of acute nonlymphocytic leukemia (ANLL) is relatively uncommon. The incidence of clinical disease is approximately 10%. Patients at highest risk of CNS involvement include younger patients and those with monocytic variants, hyperleukocytosis, or an inversion of chromosome 16. The median overall survival in patients with clinical CNS disease is 3-4 months. This case illustrates a rare outcome for this disease.
Methods A 20 year old previously healthy female presented with a sore throat, generalized weakness, subjective fevers and heavy menstrual cycle. CBC showed a WBC count of 306,000, a hematocrit of 15%, and a platelet count of 22,000. There were 97% blasts with occasional Auer rods seen on the peripheral smear. A bone marrow aspirate confirmed the diagnosis of ANLL. The patient underwent leukopheresis and induction chemotherapy with intravenous (IV) cytarabine and daunorubicin. A bone marrow aspirate at two weeks showed no blasts present. The patient subsequently received two cycles of consolidation chemotherapy with the same agents. Two months after completion of consolidation chemotherapy, she presented with meningismus and a WBC count of 146,000. A lumbar puncture showed a WBC count of 684 with an elevated opening pressure and the diagnosis of relapsed ANLL with CNS involvement was made.
Results The patient received re-induction chemotherapy with IV cytarabine and daunorubicin as well as intrathecal (IT) methotrexate. Her prolonged hospital course was complicated by the development of bowel and bladder incontinence as well as bacteremia requiring intensive care unit transfer. CSF examination prior to hospital discharge showed no blasts. The patient was then seen in the hematology clinic for weekly IT methotrexate for one month followed by monthly IT methotrexate for one year. She was also treated with monthly IV vincristine, IV cytarabine, and oral prednisone, which were continued for five years. Repeat examinations of CSF remained free of blasts. This patient is now thirteen years out from her initial diagnosis of ANLL and remains in complete remission.
Conclusions Although the usual prognosis for ANLL involving the CNS is dismal, this patient attained a complete remission, which has persisted for 13 years. The maintenance regimen of chemotherapy continued for 5 years and may be the basis for her distinctly uncommon outcome.