Karen Lusky
February 2021—Granulocyte morphology may contain clues to neutrophilia etiology, and that was the focus of a CAP20 virtual presentation by Olga Pozdnyakova, MD, PhD, associate professor of pathology at Harvard Medical School and medical director of the hematology laboratory at Brigham and Women’s Hospital.
Reactive changes can mimic myeloproliferative neoplasm, but myeloproliferative neoplasm can have reactive morphology, she said. Pathologists can piece together clinical and morphological clues, “especially in concert with the clinical team, that may help them decide whether the changes are more reactive or more neoplastic in nature,” she told CAP TODAY in a follow-up interview.
Neutrophilia is defined as greater than 7.7 × 109/L or two standard deviations above the mean, and it is important to note whether it is present in the context of the left shift.
Also important to note is whether neutrophilia is accompanied by other cytoses or cytopenias and what the neutrophil morphologic changes are, Dr. Pozdnyakova said. “And as always, it is essential to review the peripheral blood smear in the context of the clinical picture. Is neutrophilia symptomatic or incidental? How long has it been present? Is the patient taking medications?”
The primary causes of neutrophilia are both constitutional and acquired. Leukocyte adhesion deficiency, familial myeloproliferative neoplasm, and Down syndrome are examples of constitutional etiologies. Acquired primary neutrophilias are usually associated with myeloproliferative neoplasms, CML being one of the most common, followed by chronic neutrophilic leukemia or other Philadelphia-negative myeloproliferative neoplasms, atypical chronic myeloid leukemia, or other myelodysplastic/myeloproliferative neoplasm (MDS/MPN) overlap syndromes.
Secondary neutrophilia signifies reactive changes to various conditions, she said, such as smoking, infection and inflammation, medications (growth factors and corticosteroids are most common), and stress. Neutrophilia can be part of the paraneoplastic syndrome or be seen in patients with a nonfunctioning spleen. Secondary neutrophilias are more common than primary and generally accompanied by count changes and various morphological changes, which Dr. Pozdnyakova reviewed in her presentation.
She described a 36-year-old female who presented with an absolute neutrophil count of 14,000 in the setting of ongoing infection and accompanied by the left shift (Fig. 1). Metamyelocytes, promyelocytes, and myelocytes were reported on the patient’s white blood cell differential. “The presence of anemia and low platelets are likely related to ongoing chemotherapy for primary CNS lymphoma. Review of the smear shows characteristic reactive changes of toxic granulation, cytoplasmic vacuolization, and the presence of Dohle bodies in segmented neutrophils and in bands.”