Cytoplasmic granules in leukaemic cells of the cerebrospinal fluid in a child with non-granular acute lymphocytic leukaemia.

We report a child with relapsed acute lymphocytic leukaemia in whom cytoplasmic granules were present in the leukaemic cells of the cerebrospinal fluid (CSF) but not in those of the bone marrow (BM). The leukaemic cells of the BM were of B-cell lineage whereas those of the CSF had both B-cell and myeloid antigens.