Slide 98.Extramedullary hematopoiesis, Liver

A. Brief Descriptions

  1. Definition: hematopoiesis occurs outside the bone marrow.

  2. In fetal life: hematopoiesis in liver, spleen, lymph node and thymus.

  3. In older people: replacement of other infiltrative process or increased demand of hematopoietic elements reactivation in these areas.

B. Gross Findings


C. Micro Findings

  1. Liver parenchyma: extremely hypercellular, normal licer structures are hard to identified.

  2. Sinusoids: dilated and filled with clumps of erythroid and myeloid precursors together with megakaryocytes.

  3. Erythropoiesis: predominant part; round, hyperchromatic nuclei and scanty cytoplasmà 

  4. Leukopoiesis: mature and immature (vesicular nucleus) granulocytes.

  5. Portal tract involvement: in late stage.

  6. Focal perisinusoidal fibrosis

D. Others:


E. Reference





Fig. 98-1 (LP)Liver parenchyma shows extremely hypercellular and normal structures are hard to identify.




Fig. 98-2 (LP)Hepatic sinusoids are dilated and filled with clumps of precursor cells.



Fig. 98-3 (HP)Clumps of erythroid precursors with round , hyperchromatic nuclei and scanty cytoplasm.Predominant in the slide.




Fig. 98-4 (HP)Mature and immature granulocytes.