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9 - Grade/differentiation unknown, not stated, or not applicable
Chronic erythremia [OBS]
Polycythemia rubra vera
Polycythemia with chronic cyanosis
Spent phase polycythemia
A disease in which there are too many red blood cells in the bone marrow and blood, causing the blood to thicken. The number of white blood cells and platelets may also increase. The extra blood cells may collect in the spleen and cause it to become enlarged. They may also cause bleeding problems and make clots form in blood vessels. PV arises in clonal hematopoietic stem cell, characterized by increased RBC production independent of mechanisms that normally regulate erythropoiesis.
The JAK2 mutation occurs in >96% of patients with PV, however JAK2 can also occur in other types of myeloprolific neoplasms (with less fequency). The blood and bone marrow are the primary sites of involvement. The physician also correlates the morphologic findings in BM biopsy with other clinical and laboratory findings to firmly establish the diagnosis. The patient usually presents with hypertension or vascular abnormalities; nearly 20% have an episode of DVT, myocardial ischemia, or a stroke. The patient may present with an elevated platelet count, elevated hemoglobin/hematocrit, elevated white cell count, or enlarged spleen. Treatment does not cure PV but does control it. The patient has phlebotomy (removal of blood, usually a pint every other day) until the hematocrit reaches a normal level. Then blood is removed every few months as needed.
There are three phases of Polycythemia Vera 1. Prodromal, pre-polycythemia phase 2. Overt polycythemia phase 3. Spent or post-polycythemia myelofibrosis phase
The "spent phase" of polycythemia vera is the finding of myelofibrosis in the bone marrow. The myelofibrosis is a result of the PV. This is still the same primary, polycythemia vera, with the bone marrow showing the effect of the disease. This form of myelofibrosis is different from primary myelofibrosis, which is code 9961/3.
The diagnosis of "polycythemia" by itself is not reportable. To be reportable the diagnosis must be polycythemia vera, or some of the other alternate names listed above in the alternate names section.
Definitive Diagnostic Methods
Bone marrow biopsy
Janus kinase-2, JAK2
No immunophenotype features have been reported
Blood thinners, anti-coagulant medications, sometimes aspirin