Granular acute lymphoblastic leukemia in children. "Aieop Cooperative Group for Cytology of Acute Leukemias"

Abstract

Background: Granular acute lymphoblastic leukemia (ALL) is a rare morphological variant of ALL, characterized by cytoplasmic azurophil granules or inclusions, positive for aspecific esterase and acid phosphatase, with heterogeneous features at the ultrastructural level.

Methods: In an attempt to determine whether the presence of granules or inclusions marks a biologically distinct variety of ALL with peculiar clinical features, a prospective morphological review was undertaken of children entering AIEOP protocols for ALL in the period from 1985 to 1989.

Results: Of 531 cases examined, 16 (3%) were found to have greater than 1% granular bone marrow blasts, with 7 cases (1.3%) having greater than 10%. The presence of granules or inclusions was associated with the immunophenotype of "common" ALL. There was no clear association with FAB type L1 or L2 nor with particular clinical or hematological findings at presentation. Complete remission was achieved in all cases; one patient died of infection in remission at 3 months and 2 patients relapsed after 12 and 32 months, respectively, while the others are still in remission after a minimum follow-up of 24 months.

Conclusions: In conclusion, granular morphology seems to have no prognostic importance in children ALL.