MacrocytosisMacrocytosis is the enlargement of red blood cells with near-constant hemoglobin concentration, and is defined by a mean corpuscular volume (MCV) of greater than 100 femtolitres (the precise criterion varies between laboratories). The enlarged erythrocytes are called macrocytes or megalocytes (both words have roots meaning "big cell"). As a symptom its cause may be relatively benign and need no treatment or it may indicate a serious underlying illness.
MegakaryocyteA megakaryocyte (mega- + karyo- + -cyte, "large-nucleus cell") is a large bone marrow cell with a lobated nucleus that produces blood platelets (thrombocytes), which are necessary for normal clotting. In humans, megakaryocytes usually account for 1 out of 10,000 bone marrow cells, but can increase in number nearly 10-fold during the course of certain diseases. Owing to variations in combining forms and spelling, synonyms include megalokaryocyte and megacaryocyte.
Lymphoproliferative disordersLymphoproliferative disorders (LPDs) refer to a specific class of diagnoses, comprising a group of several conditions, in which lymphocytes are produced in excessive quantities. These disorders primarily present in patients who have a compromised immune system. Due to this factor, there are instances of these conditions being equated with "immunoproliferative disorders"; although, in terms of nomenclature, lymphoproliferative disorders are a subclass of immunoproliferative disorders—along with hypergammaglobulinemia and paraproteinemias.
Platelet transfusionPlatelet transfusion, also known as platelet concentrate, is used to prevent or treat bleeding in people with either a low platelet count or poor platelet function. Often this occurs in people receiving cancer chemotherapy. Preventive transfusion is often done in those with platelet levels of less than 10 x 109/L. In those who are bleeding transfusion is usually carried out at less than 50 x 109/L. Blood group matching (ABO, RhD) is typically recommended before platelets are given.
Acute erythroid leukemiaAcute erythrocyte leukemia is a rare form of acute myeloid leukemia (less than 5% of AML cases) where the myeloproliferation is of erythrocytic precursors. It is defined as type "M6" under the FAB classification. The most common symptoms of AEL are related to pancytopenia (a shortage of all types of blood cells), including fatigue, infections, and mucocutaneous bleeding. Almost half of people with AEL exhibit weight loss, fever and night sweats at the time of diagnosis.
Hemophagocytic lymphohistiocytosisHemophagocytic lymphohistiocytosis (HLH), also known as haemophagocytic lymphohistiocytosis (British spelling), and hemophagocytic or haemophagocytic syndrome, is an uncommon hematologic disorder seen more often in children than in adults. It is a life-threatening disease of severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages, characterised by proliferation of morphologically benign lymphocytes and macrophages that secrete high amounts of inflammatory cytokines.
Hairy cell leukemiaHairy cell leukemia is an uncommon hematological malignancy characterized by an accumulation of abnormal B lymphocytes. It is usually classified as a subtype of chronic lymphocytic leukemia (CLL). Hairy cell leukemia makes up about 2% of all leukemias, with fewer than 2,000 new cases diagnosed annually in North America and Western Europe combined. Hairy cell leukemia (HCL) was originally described as histiocytic leukemia, malignant reticulosis, or lymphoid myelofibrosis in publications dating back to the 1920s.
White blood cell differentialA white blood cell differential is a medical laboratory test that provides information about the types and amounts of white blood cells in a person's blood. The test, which is usually ordered as part of a complete blood count (CBC), measures the amounts of the five normal white blood cell types - neutrophils, lymphocytes, monocytes, eosinophils and basophils - as well as abnormal cell types if they are present. These results are reported as percentages and absolute values, and compared against reference ranges to determine whether the values are normal, low, or high.
