#00064380

Neutrophil hypersegmentation is defined as the presence of neutrophils with six or more nuclear lobes or the presence of more than 3% of neutrophils with at least five nuclear lobes.

Neutrophil hypersegmentation can be a diagnostic clue to megaloblastic anemia, but is a non-specific finding and may be seen in patients with iron deficiency anemia, myeloid neoplasms, patients undergoing treatment with hydroxyurea or other medications, following granulocytes colony stimulating factor (G-CSF) administration and other conditions.

This patient had a JAK2 mutated myeloproliferative neoplasm.