Anatomy of the bone. The bone is made up of compact bone, spongy bone, and bone marrow. Compact bone makes up the outer layer of the bone. Spongy bone is found mostly at the ends of bones and contains red marrow. Bone marrow is found in the center of most bones and has many blood vessels. There are two types of bone marrow: red and yellow. Red marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets. Yellow marrow is made mostly of fat.
A blood stem cell may become a myeloidstem cell
or a lymphoid
stem cell. A lymphoid stem cell becomes a white blood cell. A myeloid stem cell becomes one of three types of mature blood cells:
Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.
In myeloproliferative neoplasms, too many blood stem cells become one or more types of blood cells. The neoplasms usually get worse slowly as the number of extra blood cells increases.
There are 6 types of chronic myeloproliferative neoplasms.
The type of myeloproliferative neoplasm is based on whether too many red blood cells, white blood cells, or platelets are being made. Sometimes the body will make too many of more than one type of blood cell, but usually one type of blood cell is affected more than the others are. Chronic myeloproliferative neoplasms
include the following 6 types:
These types are described below. Chronic myeloproliferative neoplasms sometimes become acute leukemia, in which too many abnormal
white blood cells are made.
Tests that examine the blood and bone marrow are used to detect (find) and diagnose chronic myeloproliferative neoplasms.
The following tests and procedures may be used:
Physical exam
and history: An exam of the body to check general signs
of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
The amount of hemoglobin
(the protein
that carries oxygen) in the red blood cells.
The portion of the blood sample made up of red blood cells.
Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.
Peripheral blood smear: A procedure in which a sample of blood is checked for the following:
Whether there are red blood cells shaped like teardrops.
Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs
and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.
Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist
views the bone marrow, blood, and bone under a microscope
to look for abnormal cells.Bone marrow aspiration and biopsy. After a small area of skin is numbed, a bone marrow needle is inserted into the patient’s hip bone. Samples of blood, bone, and bone marrow are removed for examination under a microscope.
Cytogenetic analysis: A test in which cells in a sample of blood or bone marrow are viewed under a microscope to look for certain changes in the chromosomes. Certain diseases or disorders
may be diagnosed
or ruled out based on the chromosomal changes.
Genemutation
test: A laboratory test
done on a bone marrow or blood sample to check for mutations in JAK2, MPL, or CALR genes. A JAK2 gene mutation is often found in patients with polycythemia vera, essential thrombocythemia, or primary myelofibrosis. MPL or CALR gene mutations are found in patients with essential thrombocythemia or primary myelofibrosis.
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