Canterbury DHB

Context

Classification

Lymphoblastic leukaemia, synonymous with acute lymphoblastic leukaemia (ALL) and lymphoblastic lymphoma (LBL), are overlapping clinical entities caused by lymphoblasts of T or B origin (precursor lymphoid neoplasms). The WHO Classification of Tumours of Haemopoietic and Lymphoid Tissues (2008, p168), states:

“By convention the term lymphoma is used when the process is confined to a mass lesion with no or minimal evidence of peripheral blood and bone marrow involvement. With extensive marrow and blood involvement, lymphoblastic leukaemia is the appropriate term. If the patient presents with a mass lesion and lymphoblasts in the bone marrow, the distinction between leukaemia and lymphoma is arbitrary. For many treatment protocols a figure of 25% BM blasts is used as the threshold for defining leukaemia.”

Precursor B-ALL is more common than T-ALL, accounting for >90% of paediatric and 75% of adult cases. T-LBL is more common than B-LBL, comprising >90% of lymphoma presentations.

These are the main types of precursor Acute Lymphoblastic Leukaemia recognised by the WHO Classification:

In contrast, Burkitt leukaemia is classified by WHO amongst Mature B-cell neoplasms as one presentation of Burkitt lymphoma. Burkitt lymphoma is treated differently from precursor lymphoid neoplasms and is covered in the Lymphoma chapter of this Red Book.

About this Canterbury DHB document (8842):

Document Owner:

Peter Ganly (see Who's Who)

Issue Date:

November 2018

Next Review:

November 2021

Keywords:

Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document. Disclaimer

Topic Code: 8842