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The Pelger-Huët anomaly refers to a benign, inherited neutrophil nuclear abnormality marked by hypolobulated nuclei, commonly bilobed, without any associated functional impairment. However, when similar morphological features arise in individuals without a family history or when associated with pathological conditions, the term "pseudo-Pelger-Huët anomaly" (PPHA) is applied. Its identification can provide vital diagnostic and prognostic insights, especially in cases where the clinical picture is ambiguous.

Neutrophils affected by PPHA usually present with bilobed or unsegmented nuclei and abnormally condensed chromatin. These features can closely mimic the congenital form but are typically more heterogeneous and may coexist with dysplastic changes in other cell lines.

PPHA is most commonly observed in Myelodysplastic syndromes (MDS), Acute myeloid leukemia (AML), Chronic myelogenous leukemia (CML), severe infections (e.g., sepsis), Drug exposure: Agents like tacrolimus, sulfonamides, and chemotherapeutic agents have been implicated.

It is believed that the morphological changes result from acquired mutations or toxic effects impacting nuclear segmentation and maturation pathways in granulocytes.

Diagnosis is primarily morphological, based on examination of peripheral blood smears or bone marrow aspirates. However, distinguishing between inherited and acquired forms is crucial and may requires detailed clinical history and family background, assessment for dysplasia in other hematopoietic lineages & cytogenetic or molecular studies, especially in suspected cases of MDS or AML. While PPHA in isolation may not cause clinical symptoms, its presence can be a harbinger of serious underlying conditions. In patients with unexplained cytopenias or abnormal blood counts, the identification of pseudo-Pelger forms should prompt further hematologic investigation. In some settings, such as post-chemotherapy, it may reflect transient marrow suppression. The pseudo-Pelger-Huët anomaly represents more than just a morphological curiosity. It is a potentially vital clue pointing toward significant hematologic or systemic disease.