The proposed revised World Health Organization criteria for the diagnosis of polycythemia vera (p. vera) requires two major criteria and one minor criterion or the first major criterion together with two minor criteria.
The age-adjusted incidence of carcinoid tumors worldwide is approximately 2 per 100,000 persons.[1,2] The average age at diagnosis is 61.4 years. Carcinoid tumors represent about 0.5% of all newly diagnosed malignancies.[2,3]
Carcinoid tumors are rare, slow-growing tumors that originate in cells of the diffuse neuroendocrine system. They occur most frequently in tissues derived from the embryonic gut. Foregut tumors, which account for up to 25% of cases, arise...
Hemoglobin of more than 18.5 g/dL in men, 16.5 g/dL in women, or elevated red cell mass greater than 25% above mean normal predicted value.
Presence of JAK2 617V greater than F or other functionally similar mutations, such as the exon 12 mutation of JAK2.
Bone marrow biopsy showing hypercellularity with prominent erythroid, granulocytic, and megakaryocytic proliferation.
Serum erythropoietin level below normal range.
Endogenous erythroid colony formation in vitro.
Other confirmatory findings no longer required for diagnosis include:[2,3,4]
Oxygen saturation with arterial blood gas greater than 92%.
Thrombocytosis (>400,000 platelets/mm3).
Leukocyte alkaline phosphatase (>100 units in the absence of fever or infection).
There is no staging system for this disease.
Patients have an increased risk of cardiovascular and thrombotic events and transformation to acute myelogenous leukemia or primary myelofibrosis.[5,6,7] Age older than 65 years and a history of vascular events are independent predictors of thrombosis.[5,8]
The primary therapy for p. vera includes intermittent, chronic phlebotomy to maintain the hematocrit below 45%, and this recommendation has been confirmed in a randomized, prospective trial, which demonstrated lower rates of cardiovascular death and major thrombosis using this hematocrit target .[9,10] The target level for women may need to be lower (e.g., hematocrit <40%), but there are no empiric data to confirm this recommendation.
Complications of phlebotomy include:
Progressive and sometimes extreme thrombocytosis and symptomatology related to chronic iron deficiency, including pica, angular stomatitis, and glossitis.
Dysphagia that is the result of esophageal webs (very rare).
Possibly muscle weakness.
(Refer to the PDQ summary on Oral Complications of Chemotherapy and Head/Neck Radiation for more information.)
In addition, progressive splenomegaly or pruritus not controllable by antihistamines may persist despite control of the hematocrit by phlebotomy. (Refer to the PDQ summary on Pruritus for more information.) If phlebotomy becomes impractical, hydroxyurea or interferon-alpha can be added to control the disease.