Cerebrospinal fluid ferritin in patients with leukaemia and malignant lymphoma.

To evaluate whether cerebrospinal fluid (CSF) ferritin could be of diagnostic value in haematological malignancies with central nervous system (CNS) involvement, the ferritin concentration was measured in 21 patients with acute leukaemia and lymphoma. Of the 17 patients without CNS involvement, 16 had CSF ferritin values in the normal range (2-7 micrograms/l); 1 patient had an elevated value, probably due to blood contamination in connection with a very high serum ferritin level. 4 patients had tumour invasion of the CNS indicated by the presence of blastic cells in the CSF; CSF ferritin levels in these patients were likewise in the normal range. There was no difference between CSF ferritin values in patients with and without CNS involvement. With the present assay, measurement of CSF ferritin appears to be irrelevant in the evaluation of CNS invasion in haematological malignancies.