Role of neuroimaging in children with acute lymphoblastic leukemia and central nervous system involvement at diagnosis.

BACKGROUND: Each year approximately 200 children and adolescents are diagnosed with acute lymphoblastic leukemia (ALL) in the five Nordic countries, and 3% of these have central nervous system (CNS) involvement confirmed by leukemic cells in the cerebrospinal fluid (CSF) or neurological symptoms. We sought to determine the significance of neuraxis imaging in such patients.

PROCEDURE: Magnetic resonance images of children aged 1-17.9 with CNS leukemia at diagnosis of ALL were centrally reviewed and clinical data were retrieved from the medical records and the Nordic leukemia registry. Patients were diagnosed in the period 2000-2012 in Sweden, Finland, or Denmark.

RESULTS: The cohort comprised 1,877 patients, and 66 (3.5%) had CNS involvement. Forty-five percent (30/66) had CNS related symptoms. Symptoms included vomiting, facial palsy, headache, visual symptoms, and impaired hearing. CNS imaging was performed in 32 of 66 children (48%), and confirmed CNS involvement in 6 of 21 patients with symptoms (29%) and 5 of 11 (45%) without (P = 0.44). There was no difference in the overall survival between CNS-positive patients with and without signs of leukemic involvement by imaging (P = 0.53).

CONCLUSIONS: Radiological imaging of asymptomatic children with CNS leukemia at diagnosis lacks clinical importance, but may be useful in patients with cranial nerve symptoms and negative CSF, as well as for follow-up. Imaging of symptomatic patients is warranted in order to exclude other causes underlying the symptoms.