Abstract
A study of an 11-year-old boy with polycythemia is reported. His laboratory tests showed erythrocytosis (RBC>8 × 106/, μl) without any of splenomegaly, leukocytosis or thrombocytosis. The serum vitamin B12 levels were within the normal range. An erythroid colony assay of his bone marrow cells showed normal levels. Serum erythropoietin levels were elevated (33.2-80.6 mU/ml), but the regulation was thought to be normal. These findings did not fulfill the criteria of polycythemia vera by the American Society of Polycythemia Study Group. The patient was diagnosed to have secondary polycythemia of an unknown origin after excluding heart disease or other causes of erythrocytosis. He was treated with six phlebotomies over a period of six months without worsening of the erythrocytosis.
