Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Abnormal

Basophils (increased)*


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› Microscopic Features:

• 2-3x larger than a mature RBC
• Low nuclear to cytoplasmic ratio (more cytoplasm than nucleus)
• Nucleus is mature and usually with 2-3 lobes connected by thin chromatin filament
• Nucleoli are absent
• More cytoplasm with only secondary granules
• Secondary (specific) granules are Basophilic (blue-violet) and obscure the underlying nucleus

› Normal % blood-PB, marrow-BM, lymphoid tissue-LN:

• PB: Very Rare (5th most common WBC in blood, after neutrophils, lymphocytes, monocytes, and Eosinophils)
• BM: Rare scattered
• LN: None

› May Resemble:

• Eosinophil [Compare]
• Segmented Neutrophil [Compare]
• Pseudo-Pelger Huet Neutrophil [Compare]
• Band Neutrophil [Compare]
• Neutrophil with toxic granules [Compare]
• Promyelocyte [Compare]
• Mast Cell

› Differential Diagnoses:

Increased in: CML accelerated phase AML (rare variants) Infection (e.g. varicella) Hypersensitivity reactions (sometimes)

› Classic Immunophenotype:

• CD45dim+
• Low SSC (Side light scatter)
• CD11b+
• CD13+
• CD16-
• CD15-

› Cartoon Image:


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› Misc:

• Increased basophils may be associated with some myeloid neoplasms such as CML, or some infections or some hypersensitivity reactions