Which FAB group of acute lymphoblastic leukemias has basophilic cells with prominent cytoplasmic vacuoles?

The correct choice points to L3 as the FAB group of acute lymphoblastic leukemias characterized by basophilic cells with prominent cytoplasmic vacuoles. L3 is associated with the presence of Burkitt lymphoma, which demonstrates this particular cytological feature. The vacuoles in L3 cells result from the lipid accumulation that is typically seen in these aggressive leukemias.

In the context of the FAB classification system, L1 and L2 are primarily defined by their cellular morphology and blast cell characteristics. L1 consists of small, homogenous blasts with scant cytoplasm and a high nuclear-to-cytoplasmic ratio. L2, on the other hand, includes larger blasts that can show more variation in size and chromatin pattern but does not exhibit the same prominent vacuolation seen in L3. Thus, the distinguishing feature of basophilic cells with vacuoles is a critical identifier for L3 in diagnosing and categorizing the specific subtype of acute lymphoblastic leukemia.