Images of Pelger-Huet Anomaly in various peripheral blood smears showing numerous hyposegmented neutrophils with mature clumped chromatin. From MLS Collection, University of Alberta.

Image 1: 50x oil immersion. https://doi.org/10.7939/R3DB7W572

Image 2: 50x oil immersion. https://doi.org/10.7939/R32Z13500

Image 3: 50x oil immersion. https://doi.org/10.7939/R3Z60CH59

PBS Key Features:^1-4

Neutrophil nuclei appear hyposegmented – can appear as a single round nucleus (unilobed, homozygous Pelger-Huet Anomaly) or dumbbell shaped (bilobed, heterozygous Pelger-Huet Anomaly). Anomaly is differentiated from a left shift by displaying mature chromatin pattern, abundant cytoplasm (low nuclear:cytoplasmic ratio), mature granulation, and an absence of toxic changes.

Congenital Pelger-Huet: granulocytes show normal granulation, 50-90% of neutrophils are affected.

Pseudo Pelger-Huet: seen in leukocyte malignancies and Myelodysplastic Syndrome, hypogranulation and other Dy’s plastic features may be present, 10-30% of neutrophils are affected.

Clinical Significance and Cause:^1,3,5

Pelger-Huet Anomaly is benign and cell function is normal. Psuedo Pelger-Huet may indicate leukocyte malignancies and myelodysplasia.

Congenital: Lamin β-receptor gene mutation.

Acquired (Pseudo-Pelger-Huet): Hematologic malignancies such as myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), myeloproliferative neoplasms (MPNs). Pseudo-Pelger-Huet may also be seen during  infections, and drug interactions.

Inheritance Pattern:^1-3,5

Autosomal dominant

CBC:²

Congenital Pelger-Huet: Cytopenias often absent

Pseudo-Pelger-Huet: Cytopenias often present

References:

1. Turgeon ML. Nonmalignant Disorders of Granulocytes and monocytes. In: Clinical hematology: theory and procedures. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1999. p. 206-16.

2. Cunningham JM, Patnaik MM, Hammerschmidt DE, Vercellotti GM. Historical perspective and clinical implications of the Pelger-Huet cell. Am J Hematol [Internet]. 2009 Oct 20 [cited 2018 Jul 10];84(2):116–9. Available from: https://doi.org/10.1002/ajh.21320

3. Marionneaux S. Nonmalignant leukocyte disorders. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 475-97.

4. Harmening DM, Marty J, Strauss RG. Cell biology, disorders of neutrophils, infectious mononucleosis, and reactive lymphocytosis. In: Clinical hematology and fundamentals of hemostasis. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 305-30.

5. Landis-Piwowar K. Nonmalignant disorders of leukocytes: granulocytes and monocytes. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 388-407.