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

Increased Mature Monocytes*


Click Here for Full Size



Microscopic Features:
  • 3-4x larger than a mature RBC
  • Lower nuclear to cytoplasmic ratio because of increased cytoplasm
  • Kidney shaped Indented Nucleus with mature chromatin (clumped)
  • Nucleoli is absent
  • Cytoplasm is abundant, gray to pale blue and lacks granules
  • vacuoles are commonly noted in cytoplasm
Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
  • PB: Monocytes are the 3rd most common WBC in the blood (after neutrophils and lymphocytes)
  • BM: Scattered monocytes can be seen in the bone marrow (some as histiocytes/macrophages)
  • LN: Scattered monocytes can be seen in the bone marrow (some as histiocytes/macrophages)
May Resemble: Differential Diagnoses:

If increased in blood or increased numbers in bone marrow:
Chronic Myelomonocytic Leukemia
Chronic neutropeniacollagen
Autoimmune (sometimes)
Chronic infections (e.g. CMV, tuberculosis, etc.)

Classic Immunophenotype:
  • N/A
Cartoon Image:



Click and drag
RBC
for direct comparison

Misc:
  • Increased monocytes can be associated with many processes including but not limited to infectious etiologies.



Content Editors/Website Administrators:
Hooman H. Rashidi, MD; John C. Nguyen, MD