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

Plasmablast (Immature plasma cell)*






Microscopic Features:
  • 3-4x larger than a mature RBC
  • Round eccentricly placed nucleus with less mature chromatin
  • Moderate amount of basophilic (blue) cytoplasm with prominent perinuclear hof (clearing)
  • Nucleoli are Prominent
Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
  • PB: None
  • BM: None
  • LN: None
May Resemble:
  • Polychromatophilic normoblast
  • Plasma cell (mature)
  • Myeloblast
  • Osteoblast
  • Pronormoblast
  • Monoblast
  • Reactive lymphocyte
Differential Diagnoses:

Plasma cell myeloma (plasmablastic form)
Plasmablastic lymphoma
Plasma cell leukemia

Classic Immunophenotype:
  • CD138+
  • CD38 bright+
  • CD19-
  • CD56- (more common)
  • CD20-
  • Cytoplasmic light chain restricted (kappa only or lambda only)
Cartoon Image:



Misc:
  • Rarely found in normal bone marrow and rarely noted in non-neoplastic conditions