Presence of SCF/CXCL12 double positive large blast-like cells at the site of cutaneous extramedullary hematopoiesis.

Extramedullary hematopoiesis (EMH) is observed in the fetal liver and the spleen under physiological conditions, but can rarely occur as pathologic condition after birth. EMH is observed in various anatomical sites in patients with hypoxia-inducing conditions, such as idiopathic myelofibrosis. The nature of the microenvironment for the maintenance of hematopoietic stem cells (HSCs) in EMH is unclear. Recent studies showed that mesenchymal stem/stromal cell (MSC)-derived cells, that can differentiate into various types of cells, play critical roles in the formation of hematopoietic niches. This article is protected by copyright. All rights reserved.