Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Extramedullary hematopoiesis (EMH)
- Radiologic Findings
- Axial and coronal chest CT images (Figures 1 & 2) demonstrate a multilobulated, homogeneously enhancing mass along the right side of T8-11 vertebral body. No significant interval change was seen, compared to CT images obtained 2 years ago (not shown). PET-CT (Figure 3) demonstrate no FDG uptake. The patient had been diagnosed as myelodysplastic syndrome (MDS) on bone marrow biopsy, and the paraspinal mass biopsy revealed ‘Mainly bone marrow with hematopoietic cells’.
- Brief Review
- Extramedullary hematopoiesis (EMH) is the proliferation of hematopoietic cells outside of the bone marrow in response to production of too few blood cells to satisfy the body’s demand. This is caused by either bone marrow replacement disease (myelofibrosis or chronic myelogenous leukemia) or hemolytic anemia (thalassemia, sickle cell anemia, or hereditary spherocytosis). The liver, spleen, kidney, lymph nodes, and posterior mediastinum are the most common sites of EMH.
Intrathoracic EMH may manifest as a paraosseous mass, interstitial pulmonary abnormality, pleural mass, or hemothorax, either alone or in combination. Mediastinal lesions most commonly occur in the posterior mediastinum due to herniation of myeloid tissue through the thin cortical bone of the posterior ribs and/or activation of extramyeloid hematopoietic cells. The paraspinal masses and rib expansion are the most common manifestation of intrathoracic EMH. The paraspinal masses have to be differentiated from lymphadenopathy and neurogenic tumors. EMH usually regresses or disappears after treatment with blood transfusion and hydroxyurea, splenectomy in cases of spherocytosis, or radiation therapy.
- Please refer to
Case 598, Case 708, -
- References
- 1. Yeom SY, Lim JH, Han KN, Kang CH, Park IK, Kim YT. Extramedullary Hematopoiesis at the Posterior Mediastinum in Patient with Hereditary Spherocytosis: A Case Report. Korean J Thorac Cardiovasc Surg. Apr 2013; 46(2): 156–158.
2. Yahya M. Berkmen and Benjamin A. Zalta. Case 126: Extramedullary Hematopoiesis Radiology 2007; 245: 905-908
- Keywords
- Paravertebral, Others,