EMH With Megakaryocyte
This is a skin biopsy specimen with extramedullary hematopoiesis (EMH), as evidenced by the large megakaryocyte .
TERMINOLOGY
Abbreviations
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Extramedullary hematopoiesis (EMH)
Definitions
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Formation of blood cells (including nucleated red blood cells, lymphocytes, and megakaryocytes) outside of bone marrow
Occurs most commonly in liver and spleen
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Also found in other organs, including lymph nodes, kidney, adrenal, gastrointestinal tract, lung, breast, central nervous system
Hematopoiesis occurs in skin early in embryonic life
ETIOLOGY/PATHOGENESIS
Viral Infection
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Has been reported in skin in neonates with intrauterine viral infections including
Cytomegalovirus
Coxsackievirus
Rubella
Hematopoietic Disorders
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In neonates, EMH occurs in congenital hematologic disorders including
Hemolytic disease of newborn
Twin transfusion syndrome
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In adults, EMH is seen with hematopoietic disorders
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