Pelger-Huët Anomaly

Pelger-Huët Anomaly

Kathryn Foucar, MD

This blood smear shows a neutrophil with a hyposegmented nucleus in acquired PHA in a patient on numerous medications. Note that the cytoplasm is normal.

This blood smear shows 2 mononuclear (Stodtmeister) PHA-type neutrophils in an asymptomatic young adult with familial PHA. Note lack of segmentation and highly condensed nuclear chromatin.



  • Pelger-Huët anomaly (PHA)


  • Nuclear hyposegmentation of neutrophils and other granulocytic cells resulting in either bilobed (pincenez) or mononuclear (Stodtmeister) morphology

  • Familial and acquired forms


Multifactorial Causes

  • Autosomal dominant familial PHA

  • Numerous medications linked to acquired, nonneoplastic PHA

    • Sulfasoxazole

    • Sulfonamides

    • Mycophenolate mofetil

    • Myelosuppressive agents

    • Colchicine

    • Ganciclovir

    • Valproic acid

    • Paclitaxel

    • Other medications

  • Chronic infections can cause acquired PHA

    • HIV

    • Tuberculosis

    • Mycoplasma pneumonia

    • Influenza

    • Malaria

  • Clonal myeloid neoplasms linked to acquired PHA

    • Myelodysplasia (MDS)

    • Acute myeloid leukemia (AML)

    • Myelodysplastic/myeloproliferative neoplasms

    • Neutrophils are component of neoplastic clone

Pathogenesis of Familial PHA

  • Autosomal dominant

    • Mutations in lamin β-receptor (LBR) gene at 1q41-43

    • Results in defects in scaffolding proteins that control shape of nuclear membrane

    • Nuclear hypolobation results from reduced levels of LBR protein

    • All granulocytic lineages affected

    • Neutrophil function normal

  • Neutrophil migratory defect linked to soft tissue infections

Pathogenesis of Acquired Secondary, Nonneoplastic PHA

  • Unknown

Pathogenesis of Acquired, Clonal PHA in Myeloid Neoplasms

  • Possible acquired mutations in LBR

  • Possible apoptotic defect with resulting dense, nonsegmented nuclei

  • Possible acquired clonal 17p deletion linked to prominent PHA



  • Incidence

    • 1 per 5,000 population for familial PHA

    • Highly variable for acquired PHA dependent upon cause

  • Age

    • Present at birth in familial PHA

    • Wide age range for acquired PHA dependent upon cause

  • Gender

    • No gender predilection except for HIV-associated acquired PHA, which is more common in males

  • Ethnicity

    • No ethnic predilection


  • Incidental finding in familial PHA

  • Clinical findings variable in acquired PHA dependent on underlying cause

Jun 13, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Pelger-Huët Anomaly
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