Today, at our inaugural Hillcrest Primary Care Morning Report, we discussed the case of an elderly woman who presented with night sweats and splenomegaly and was found to have a significant leukocytosis. A peripheral blood smear revealed increased bands, metamyelocytes, myelocytes, and basophils. A BCR/ABL1 PCR was sent and returned positive, confirming the diagnosis of chronic myelogenous leukemia. She improved with initiation of imatinib.
With the help of our primary care expert, Dr. Lawrence Ma, a proud alumnus of the residency program, we talked about the most common etiologies of leukocytosis in the outpatient setting. Non-malignant causes of leukocytosis include stress (e.g., trauma), exercise, smoking, medications, acute/chronic infection, chronic inflammation, bone marrow activation, and asplenia. Malignant causes of leukocytosis include chronic myelogenous leukemia (CML), chronic lymphocytic leukemia (CLL), other myeloproliferative/lymphoproliferative disorders, and various solid tumors.
The peripheral blood smear can offer important diagnostic clues. At UCSD and the VA, you can digitally view blood smears using CellaVision. The appearance of blasts should raise concern for an acute leukemia, whereas an increase in more mature blood cells of the myeloid or lymphoid lineage could signal the presence of CML or CLL, respectively. As Dr. Ma pointed out, the decision to refer a patient to Hematology/Oncology is contingent upon a number of factors, including severity/duration of leukocytosis, B symptoms (fevers, night sweats, weight loss), hepatosplenomegaly, lymphadenopathy, bleeding, bruising, and petechiae. Presence of blasts, other immature forms, increased basophils, monomorphic lymphocytosis, and other cell line abnormalities are all suggestive of a hematologic disorder.
Remember, CML is a diagnosis that any primary care physician can make! Classified as a myeloproliferative neoplasm, CML is associated with the t(9;22) translocation (Philadelphia chromosome) and BCR/ABL1 fusion. Diagnosis is confirmed by FISH (for the translocation) and/or PCR (for the BCR/ABL1 fusion transcript). Treatment is with BCR/ABL1-specific tyrosine kinase inhibitors, which include imatinib and dasatinib.
Thank you, Dr. Ma, for everything you do for your patients and for being part of UCSDIM history!
Medical Spanish Word of the Day: el bazo = spleen