What is extramedullary hematopoiesis?
Extramedullary hematopoiesis (EH) is defined as hematopoiesis occurring in organs outside of the bone marrow; it occurs in diverse conditions, including fetal development, normal immune responses, and pathological circumstances.
What is extramedullary hematopoiesis and where does it occur?
Extramedullary hematopoiesis (EMH or sometimes EH) refers to hematopoiesis occurring outside of the medulla of the bone (bone marrow). It can be physiologic or pathologic. Physiologic EMH occurs during embryonic and fetal development; during this time the main site of fetal hematopoiesis are liver and the spleen.
How do you test for extramedullary hematopoiesis?
Fine-needle biopsy can confirm the diagnosis. Extramedullary hematopoiesis occurs as a compensatory mechanism for abnormal hematopoiesis when normal red marrow is unable to function because of deficiency disorders or because of various pluripotent stem cell disorders.
What is the most common posterior mediastinal tumor?
Neurogenic tumors, to include nerve sheath and sympathetic ganglion tumors, represent the most common posterior mediastinal masses. Most lesions, especially if benign, are asymptomatic. Nerve sheath tumors, such as schwannoma and neurofibroma, are most often seen in patients around 20-30 years of age.
Is extramedullary hematopoiesis cancerous?
Extramedullary haematopoiesis (EMH) in the axillary lymph node of breast cancer patients is extremely rare but when encountered can represent a diagnostic challenge. We aim to highlight this incidental finding as a diagnostic pitfall which can be mistaken for metastatic carcinoma (particularly of the metaplastic type).
What triggers extramedullary hematopoiesis?
Extramedullary haematopoiesis can result in paravertebral masses caused by compensatory expansion of bone marrow in patients with severe anaemia caused by inadequate production or excessive destruction of blood cells.
How is extramedullary hematopoiesis treated?
Treatment of such cases is usually done with blood transfusions, which can reduce the hematopoietic drive for EMH. Other options include surgery, hydroxyurea, radiotherapy, or a combination of these on a case to case basis.
What would cause a mediastinal mass?
A: Depending on etiology, a mediastinal tumor can be caused by an enlarged lymph node, or a gland such as the thymus, thyroid, or parathyroid. It can also be caused by a cyst originating from the pericardium (the sac that houses the heart), the bronchus, or the esophagus.
What percentage of mediastinal masses are malignant?
Mesenchymal tumors represent approximately 6% of all masses found in the mediastinum. More than 50% of these are malignant.
Is it possible to have extramedullary hematopoiesis during adulthood?
Extramedullary hematopoiesis (EMH) implies the production of erythroid and myeloid progenitor cells outside of the bone marrow. EMH in adults is typically seen in patients with myeloproliferative neoplasms (MPNs) but its association also with other conditions, including thalassemia, has long been recognized1.
What causes extramedullary hematopoiesis in thalassemia?
Extramedullary hematopoiesis (EMH) is the production of blood cell precursors outside the bone marrow that occur in various hematological diseases. In patients with thalassemia intermedia, ineffective erythropoiesis drives compensatory EMH in the liver, pancreas, pleura, spleen, ribs and spine.