ALL L2 is described with CBC showing WBC 46 x 10^9/L and marrow with >25% lymphoblasts; MPO NEG; Sudan Black NEG; PAS POS. Which diagnosis is most consistent?

Get ready for the CAMLPR Hematology Test. Use our quizzes, flashcards, and detailed explanations to enhance your understanding. Prepare confidently for your exam!

This scenario tests distinguishing lymphoid from myeloid blasts using morphology and cytochemical stains. The marrow showing more than 25% lymphoblasts points to an acute lymphoblastic process rather than a chronic leukemia or a myeloid leukemia. The blasts being negative for myeloperoxidase and Sudan Black further supports non-myeloid lineage, since these stains highlight myeloid cells. PAS positivity is commonly seen in lymphoblasts of ALL, helping to confirm lymphoid lineage over myeloid blasts, which are usually PAS negative or variable.

Within ALL, the L2 FAB subtype describes larger, more heterogeneous lymphoblasts with more cytoplasm and irregular nuclear contours, as opposed to the small, uniform blasts seen in L1. Given the combination of a high lymphoblast fraction, negative myeloid cytochemistry, and PAS positivity, the diagnosis that fits best is Acute Lymphoblastic Leukemia, L2.