Introduction and aims Acute lymphoblastic leukaemia (ALL) is the most common paediatric malignancy. Diagnostic is very important because optimal therapy will achieve complete remission in over 95% of all patients with 75%–85% of these surviving without recurrence. CNS involvement is a major clinical problem and patients who present with CNS involvement at diagnosis are at a higher risk for treatment failure. Only 3% of patients have detectable CNS involment. Intrathecal chemotherapy may be combined with systemic infusions of methotrexate with leucovorin rescue and cranial significantly reduced CNS recurrence. Unfortunately, these therapies are associated with substantial acute and long-term neurotoxicity, and also CNS relapse remains a major therapeutic obstacle in ALL, accounting for 30% of the relapses. CNS involvement in ALL is classically defined by the presence of more than 5 leukocytes/µl and presence of blasts in the cerebrospinal fluid. The involvement of cranial nerves is also part of the diagnostic criteria for CNS involvement. Methods We present the case of a female patient 8 years and 9 months diagnosed with acute lymphoblastic leukaemia. The patient presented in our clinic for progressive neurological signs and persistent CSF modifications specific to chronic meningitis (clear CSF,>1000 elements, initially PMN and then lymphocytes, with high glucose and moderate levels of proteins). Brain and medullar MRI were normal without any significant parechymal lesions. Differential diagnostic was were difficult: we excluded multiple sclerosis, optic neuritis, bacterial and TB meningitis, autoimmune disease and other. Symptoms were attenuated during corticotherapy, but without remission and with relapsing neurological episodes. Results The presence of blasts in the cerebrospinal fluid on microscopic examination after centrifugation of CSF sample raised the acute lymphoblastic leukaemia diagnosis and allowed a properly and optimal treatment. CNS directed therapy is an essential component of management of all children.
