I get so many really good questions from my students. I post them for our class – and from time to time I post them here, too, so everyone can benefit.There are some on hematopathology in general, and on myeloma, myeloproliferative disorders, and anemia. Today’s questions cover everything from anemia to leukemia.

Q. Did you say that spherocytes can be seen in all hemolytic anemias? 

A. Yes – spherocytes can be seen in all hemolytic anemias! The main hemolytic anemias to remember are microangiopathic hemolytic anemia, autoimmune hemolytic anemia, sickle cell anemia, thalassemia, hereditary spherocytosis, and G6PD deficiency. You can see spherocytes in all of them. Two of them – warm autoimmune hemolytic anemia and hereditary spherocytosis – have only spherocytes (no other weird findings on the blood smear)!

Q. What about for Auer rods? Are they just in acute myeloid leukemia and acute promyelocytic leukemia? or all acute leukemias?

A. Auer rods only seen in malignant myeloblasts – so you only see them in acute myeloid leukemia (AML). They actually consist of a bunch of azurophilic granules all lined up in a row – who knows why they do that. They are only seen in some types of AML (including APL). So if you see them, you know you’re dealing with an AML of some kind. If you don’t see them, it still could be AML (or, it could be acute lymphoblastic leukemia).

Q. For acute leukemias, since they are stuck at blasts, does that indicate a left shift?

A. Yes – that would be true for some types of AML (the ones that have cells of the neutrophil series). It wouldn’t be true for other types of AML (the ones that have monocytic cells, or erythroid cells, for example). It’s also true for chronic myeloid leukemia (CML), because in CML, you see all the stages of neutrophil development.

Q. Are chronic myeloid leukemia and chronic lymphocytic leukemia same thing as chronic myeloproliferative and chronic lymphoproliferative disorders, respectively? 

A. Chronic myeloid leukemia (CML) is one of the chronic myeloproliferative disorders (the others are polycythemia vera, myelofibrosis, and essential thrombocythemia). And chronic lymphocytic leukemia is one of the chronic lymphoproliferative disorders (others include hairy cell leukemia, prolymphocytic leukemia, and large granular lymphocyte leukemia).

Q. For acute lymphoblastic leukemia/lymphoblastic lymphoma: if it shows up first in the blood or marrow is it acute lymphoblastic leukemia and does it involve B or T cells? and if it shows up in lymph nodes first is it lymphoblastic lymphoma and does it involve only T cells?

A. We sometimes talk about lymphoblastic lymphoma and acute lymphoblastic leukemia separately (like when we’re looking at a lymph node, we’d probably say lymphoblastic lymphoma, and when looking at a blood smear, we’d probably say acute lymphoblastic leukemia). But technically, there is just one disease: acute lymphoblastic leukemia/lymphoblastic lymphoma (ALL/LL). That’s a big mouthful though – so to make it easier, we often break up the term.

ALL/LL can be either B cell or T cell. It turns out that T cell ALL/LL often presents in the mediastinum in teenage males (because that’s where the thymus is). But not always! Sometimes it can present in the blood (and then later move to lymph nodes/mediastinum/wherever).

B-cell ALL/LL doesn’t really have a unique presentation like that – it just shows up in the blood or in lymph nodes. Some patients present with just lymph node involvement; others present with just blood/bone marrow involvement; some present with both.

So whether it presents in lymph nodes or in the blood or in the mediastinum, it’s called ALL/LL. Then you need to do special studies (like flow cytometry) to determine whether it’s B cell or T cell.