Which FAB classification of the acute lymphocytic leukemias has prominent cytoplasmic vacuolation?

The classification of acute lymphocytic leukemia (ALL) by the French-American-British (FAB) system includes three main types, with L1, L2, and L3 designating specific characteristics of the leukemic cells. L3, also known as Burkitt leukemia, is distinguished by its prominent cytoplasmic vacuolation.

In L3, the leukemic cells typically exhibit a high degree of cellular activity, which is characterized by the presence of numerous cytoplasmic vacuoles. This vacuolation arises due to the intense metabolic activity within the cells, reflecting both the proliferation of the lymphoid lineage and the accumulation of certain cellular components. The presence of these vacuoles can also be indicative of the distinct biology of this neoplasm, such as the presence of virus-related factors, particularly in some cases of Burkitt leukemia.

In contrast, the other classifications (L1 and L2) do not exhibit the same degree of cytoplasmic vacuolation. L1 features small, homogeneous lymphoblasts with scant cytoplasm, while L2 contains larger, more heterogeneous lymphoblasts that are less typically associated with vacuolation compared to L3. Therefore, the defining characteristic of prominent cytoplasmic vac