Acquired Pelger-Huët anomaly in a patient treated with valganciclovir

A follow-up blood count was performed on a 74-year-old woman diagnosed with colitis due to cytomegalovirus and under treatment with valganciclovir. The automated complete blood count revealed an abnormal white blood cells (WBC) scattergram together with WBC alert flags. The peripheral blood smear showed neutrophils with markedly hyposegmented nuclei or bilobed nuclei and very condensed chromatin or clumping chromatin all consistent with Pelger-Huët anomaly (PHA). We checked previous blood counts, ruling out an inherited PHA. We assessed the haematological, infectious and iatrogenic aetiologies for an acquired PHA. Once the valganciclovir treatment was completed and the drug was withdrawn, without changing the rest of the treatment, the morphological abnormalities of neutrophils were completely resolved. We conclude therefore that the acquired PHA presented by our patient is probably related to valganciclovir treatment.