《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：

   略.   

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:

   略.

E. Reference：

     略.

　

 

 

【 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.