Related Experiment Video
Updated: Jul 2, 2026

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis
Published on: April 10, 2012
Cutaneous extramedullary hematopoiesis in a patient with idiopathic myelofibrosis
Toshiko Miyata1, Mikio Masuzawa, Kensei Katsuoka
1Department of Dermatology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan. tosikomi@med.kitasato-u.ac.jp
Idiopathic myelofibrosis (IM) is a chronic myeloproliferative disorder and some cases of IM have extramedullary hematopoiesis. Extramedullary hematopoiesis is commonly seen in the liver, spleen and lymph nodes, but cutaneous extramedullary hematopoiesis (CEH) is very rare in cases of IM. We report a case of CEH in a 65-year-old Japanese woman with IM. This patient had many hard brownish nodules on her chest, abdomen and scalp. Histopathological examination of the nodule on her chest showed the existence of various stages of immature erythrocytes, leukocytes and megakaryocytes indicating that these hard nodules showed extramedullary hematopoiesis in the dermis. The proliferation of these immature cells in the dermis plays an important role in the pathogenesis of CEH. CEH is a very rare manifestation of IM and progresses slowly.
Idiopathic myelofibrosis (IM) is a chronic myeloproliferative disorder and some cases of IM have extramedullary hematopoiesis. Extramedullary hematopoiesis is commonly seen in the liver, spleen and lymph nodes, but cutaneous extramedullary hematopoiesis (CEH) is very rare in cases of IM. We report a case of CEH in a 65-year-old Japanese woman with IM. This patient had many hard brownish nodules on her chest, abdomen and scalp. Histopathological examination of the nodule on her chest showed the existence of various stages of immature erythrocytes, leukocytes and megakaryocytes indicating that these hard nodules showed extramedullary hematopoiesis in the dermis. The proliferation of these immature cells in the dermis plays an important role in the pathogenesis of CEH. CEH is a very rare manifestation of IM and progresses slowly.
Related Concept Videos
Overview of Hematopoiesis
Developmental Phases of Hematopoiesis
Initially, HSCs are formed in the embryonic yolk sac, a critical site for early blood cell production. These stem cells subsequently migrate to other...
Hematopoiesis
Differentiation of Common Myeloid Progenitor Cells
Bone Marrow Sampling and Transplants
The transplant begins with high doses of chemotherapy and radiation treatment, which aim to destroy the...
Regulation of Hematopoietic Stem Cells

