Extramedullary haematopoiesis is a response to the failure of erythropoiesis in the bone marrow.
This article aims to a general approach on the condition, for a dedicated discussion to a particularly involved organ, please refer to the specific articles on:
- myeloproliferative disorders
When involving an organ, extramedullary haematopoiesis causes visceromegaly occurring most often in the spleen (splenomegaly) and liver (hepatomegaly) and occasionally in the lymph nodes. Visceromegaly is best evaluated via ultrasound, CT or MRI. Lesions are typically hypermetabolic and are FDG-18 avid on PET-CT.4
However, in the less common situation where extramedullary haematopoiesis involves other tissues within the thorax, they can be seen as a posterior mediastinal mass. These paraspinal masses may be either unilateral or bilateral and have smooth, sharply delineated, often lobulated margins.
- 1. Choi H, David CL, Katz RL et-al. Case 69: extramedullary hematopoiesis. Radiology. 2004;231 (1): 52-6. doi:10.1148/radiol.2311020673 - Pubmed citation
- 2. Gumbs RV, Higginbotham-ford EA, Teal JS et-al. Thoracic extramedullary hematopoiesis in sickle-cell disease. AJR Am J Roentgenol. 1987;149 (5): 889-93. AJR Am J Roentgenol (abstract) - Pubmed citation
- 3. Holden C, Hennessy O, Lee WK. Diffuse mesenteric extramedullary hematopoiesis with ascites: sonography, CT, and MRI findings. AJR Am J Roentgenol. 2006;186 (2): 507-9. doi:10.2214/AJR.04.1788 - Pubmed citation
- 4. Roberts AS, Shetty AS, Mellnick VM, Pickhardt PJ, Bhalla S, Menias CO. Extramedullary haematopoiesis: radiological imaging features. Clinical radiology. 71 (9): 807-14. doi:10.1016/j.crad.2016.05.014 - Pubmed