Today in report, Kat Chau dropped some awesome R3 knowledge when she presented the case of a 64 yo veteran who initially presented with chronic cough and medication refill, but on further history and lab review was found to have a new leukocytosis to 43 made up primarily of lymphs and basos. On AM slide review with the attending heme/path attending there is concern for acute basophilic leukemia — a very rare subtype of acute myelogenous leukemias.
Before discussing acute basophilic leukemia however, it’s a good idea to review the basic cell lines that make up the myelogeous and lymphocytic leukemias. Remember that basophils are part of the myeloid cell line as outlined in the figure.
Acute basophilic leukemia:
Acute basophilic leukemia is a rare AML subtype, accounting for ~0.5% of cases of AML. Most sub-types of AML are neutrophilic or monocytic. Much less common causes of AML include predominant basophilic, mastocytic, eosinophilic, or myeloid dendritic subtypes.
For basophilic leukemia, the diagnosis is made by clinical evidence of an AML, the presence of a significant number of blood or marrow cells containing bastophilic granules, and the absence of the t(15:17) or BCR-ABL mutation.
ABL presents as a “classic leukemia” with anemia, thrombocytopenia, and blasts. It can occur at any age. From a cytology standpoint, ABL can be CD13 or CD33 positive.
Clinically, ABL can distinguish itself from other leukemia in that it can present with hyper-histamine type reactions including rash (usually urticarial), headaches, GI symptoms, or anaphylactoid type reactions after the initiation of chemotherapy. Patients will sometimes be pre-treated with anti-histamines prior to chemo for this very reason.
Uncommon phenotypes of acute myelogenous leukemia: basophilic, mast cell, eosinophilic, and myeloid dendritic cell subtypes: a review. PMID: 16203163