The most common neoplastic cause of basophilia is Chronic Myeloid Leukemia (CML). Basophilia is one of the most common abnormalities in the CBC at the onset of CML; it can remain the only abnormality for several months. A value of 1 x 109/L is considered suspicious for CML (which is much higher than our patients' value). Also, the percentage of basophils seems to be prognostic—higher basophil counts are correlated with poorer prognosis.
If a patient has a high count that is suspected to be a non-reactive case, further testing would be needed. Bone marrow aspiration with morphologic and cytogenetic testing and molecular testing would be the next steps.
Other neoplasms where basophilia is found, although more rarely, include the following: Primary Myelofibrosis, AML with basophilia, chronic and acute basophilic leukemia, Polycythemia Vera, and several others.
