In line with other WHO series, the 5thWHO-Hem has also generated a category of Genetic tumor syndromes to include genetic syndromes associated with increased risk for hematolymphoid tumors.
These genetic syndromes include Fanconi anemia, Ataxia telangiectasia, Bloom syndrome, and RASopathies.
According to the WHO classification, lymphomas are divided into precursor lymphoid neoplasms and mature lymphoid neoplasms, which are each further separated into neoplasms of B- or T-cell origin.
The mature lymphoid neoplasms include non-Hodgkin lymphomas (NHLs) and Hodgkin lymphomas.
The most notable change is the blast count used to define AML.
In WHO 2017, the diagnosis of AML is defined as a blast count of greater than or equal to 20% in the bone marrow and/or blood.