page_title: Extramedullary hematopoiesis
hierarchical_section_title: Extramedullary hematopoiesis
caption_attribution_description: English: High magnification micrograph showing nucleated red blood cells, as may be seen in extramedullary haematopoiesis, in an endometrial polyp. H&amp;E stain. Related images Low mag. Intermed. mag.
context_page_description: Extramedullary hematopoiesis refers to hematopoiesis occurring outside of the medulla of the bone. It can be physiologic or pathologic.
  Physiologic EMH occurs during embryonic and fetal development mainly. It has been done in many different locations, depending on the moment or the kind of hematopoiesis that is needed in that moment.
  Pathologic EMH can occur during adulthood when physiologic hematopoiesis can't work properly in the bone marrow and the hematopoietic stem cells have to migrate to other tissues in order to continue with the formation of blood cellular components. Pathologic EMH can be caused by myelofibrosis, thalassemias or disorders caused in the hematopoietic system.
context_section_description: 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 mainly. It has been done in many different locations, depending on the moment or the kind of hematopoiesis that is needed in that moment.
  Pathologic EMH can occur during adulthood when physiologic hematopoiesis can't work properly in the bone marrow and the hematopoietic stem cells (HSC) have to migrate to other tissues in order to continue with the formation of blood cellular components. Pathologic EMH can be caused by myelofibrosis, thalassemias or disorders caused in the hematopoietic system.
caption: Micrograph showing nucleated red blood cells (bottom left of image), one of the elements necessary to call extramedullary hematopoiesis, in an endometrial polyp. H&E stain.
exif: {"Image Make": "Canon", "Image Model": "Canon EOS DIGITAL REBEL XSi", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2010:11:06 00:37:42", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "192", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "9118", "Thumbnail JPEGInterchangeFormatLength": "9394", "EXIF ExposureTime": "1/10", "EXIF FNumber": "0", "EXIF ExposureProgram": "Aperture Priority", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2010:11:05 17:22:23", "EXIF DateTimeDigitized": "2010:11:05 17:22:23", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "27/8", "EXIF ApertureValue": "2147483648", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Spot", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "0", "EXIF SubSecTime": "81", "EXIF SubSecTimeOriginal": "81", "EXIF SubSecTimeDigitized": "81", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "4272", "EXIF ExifImageLength": "2848", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "8994", "EXIF FocalPlaneXResolution": "2136000/439", "EXIF FocalPlaneYResolution": "356000/73", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}