Acute lymphoblastic leukemia, positive PAS stain, bone marrow aspirate
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The blasts show strong positive reaction for PAS, observed as pink granules and globules in the blast cytoplasm ("block PAS positivity". This pattern of PAS reaction is characteristic of lymphoblasts, and represents intracytoplasmic glycogen. This leukemia had a precursor B phenotype, and the patient is now in complete remission