A 27-year-old PhD student from Egypt is referred to your clinic for assessment of neutropenia. He otherwise denies any history of recurrent infection, fever, or B symptoms. He is on no medications. He has never had blood work done prior.
- What is the most likely diagnosis in this case?
- Does this patient warrant a bone marrow biopsy?
Click for answer:
Diagnosis: chronic benign neutropenia, Duffy null
Q1: What is the most likely diagnosis in this case?
Chronic benign neutropenia with Duffy null phenotype
Q2: Does this patient warrant a bone marrow biopsy?
No
Neutropenia Differential
• MDS
• Autoimmune
• Drug-induced
• Chronic benign/Duffy-null
• Acute viral infection
• Nutritional deficiency
Chronic benign forms of neutropenia can stem from various etiologies, including inherited, idiopathic, and autoimmune. Inherited neutropenia encompasses various genetic syndromes resulting in neutropenia, such as mutations in the neutrophils elastase gene (ELANE). Autoimmune neutropenia should be considered in patients with underlying autoimmune disease with strongly positive testing. Lastly, chronic idiopathic neutropenia is a unique syndrome that often affects women of child-bearing age. Common causes for neutropenia are listed in the Box.
CBC Pearls
- Chronic benign neutropenia is usually an isolated neutropenia
- Stable neutrophil counts with no infectious symptoms are reassuring
Chronic benign neutropenia with Duffy null phenotype is a new nomenclature for the previously labelled “benign ethnic neutropenia”. This diagnosis was previously given to patients of African descent who were found to have benign, chronic neutropenia. However, these patients are now known to lack the Duffy antigen on their red blood cells, leading to a lower neutrophil level than the general population but conferring malaria protection. This is a normal, population-based range and should not cause concern. Patients should know to monitor for recurrent fever or infections and seek medical attention if they occur. Patients who have recurrent or severe bacterial infections, abnormal blood films (e.g. blasts), or other cell line abnormalities should be referred to a hematologist.