•TIA-1 and hnRNPA1 normally have nuclear and cytoplasmic distribution in contrast, In MS's hnRNPA1 nuclear depletion was observed in brain neurons.•Accumulations of TIA-1 in large SGs formed in the cytoplasm of MS's brain neurons, but not in the nucleus.•In MS's brain neurons unlike control, hnRNPA1 and TIA-1 colocalized in cytoplasmic granules in double-label staining. The gene discussed is HNRNPA1; the disease is myeloid sarcoma.