Canadian Association of Pathologists - Case of the Month, February 2007
67 year-old man with acute onset of fatigue.
Diagnosis:
The marrow was replaced by large nucleolated blasts with cytoplasm displaying large purplish granules. Normal hematopoiesis is virtually absent. Esterase stains show strong granular positivity primarily in golgi area of blasts. Myeloperoxidase stains were negative.
Diagnosis: Precursor B-lymphoblastic leukemia, granular variant.
Notes:
Granulated blasts have been described in up to 10% of precursor lymphoblastic leukemias (acute lymphoid leukemia, ALL) and has been correlated with pre-B immunophenotype and false positive histochemistry for esterase stains. As this case exemplifies, unless Auer rods are seen, it is perilous to assign lineage to leukemic blasts based solely upon morphology.
References:
Simpkins H, Shoaf F, Katz J. An acute granular lymphoid leukemia with unusual cytochemistry and immunologic phenotype. Hum. Pathol. 1987 Jan;18(1):93-5.