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Updated: May 6, 2026

In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy
Published on: September 8, 2021
Extramedullary hematopoiesis in pyogenic granuloma
Sakda Waraasawapati1, Supinda Koonmee, Hiroshi Kusama
1Department of Pathology, Toda Chuo General Hospital, Saitama, Japan; Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Abstract:
Extramedullary hematopoiesis (EMH) suggests the presence of hematopoietic stem cells (HSC) outside bone marrow. EMH has been reported, albeit rarely, in pyogenic granuloma (PG), a polypoid lobular capillary hemangioma. However, statistical data have hitherto been lacking on the actual incidence of EMH in PG. Therefore, we here reviewed 157 consecutive cases using routine diagnostic surgical slides and found unequivocal EMH in 17 (10.8%). This indicates that EMH is a rather common finding in PG, which could thus have strong potential to be an important resource for the study of HSC.
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