Granular acute lymphoblastic leukemia in a 15-year-old boy.

We report a case of a boy with acute lymphoblastic leukemia expressing granular inclusions in the cytoplasm of blastic cells. Granular lymphoblasts had mostly L2 morphology but azurophilic granules were also present in part of the cells with L3 morphology. Immunophenotyping clearly indicated a lymphoid origin of the blasts and showed positivity of HLA-DR, CD10, CD19 and CD24 markers. Cytogenetic analysis brought normal karyotype 46 XY. Molecular genetic analysis showed immunoglobulin heavy chain rearrangement (IgH R/R) and T-cell receptor gamma rearrangement pattern (TCR-gamma C/R). TCR-beta and TCR-delta did not show rearrangements. The course of the disease was favourable. The patient achieved initial complete remission within 4 weeks of protocolar treatment and the remission remains until now, 5 years from the diagnosis and three years after finishing the treatment.