View by:

Hematology and Oncology

Overview of Cancer
Approach to the Patient With Anemia
Anemias Caused by Deficient Erythropoiesis
Anemias Caused by Hemolysis
Bleeding Due to Abnormal Blood Vessels
Coagulation Disorders
Eosinophilic Disorders
Hemostasis
- Overview of Hemostasis
- Excessive Bleeding
Histiocytic Syndromes
Iron Overload
Leukemias

Leukopenias
Lymphomas
Myeloproliferative Disorders
Plasma Cell Disorders
Principles of Cancer Therapy
Spleen Disorders
Thrombocytopenia and Platelet Dysfunction
Thrombotic Disorders
Transfusion Medicine
Tumor Immunology

Hematology is the subspecialty of internal medicine concerned with disorders of the blood and blood-forming organs. Oncology is a subspecialty of internal medicine that focuses on medical treatment of cancer. Because cancers of blood-forming cells were the first for which reasonably effective chemotherapy was developed, hematology and oncology have often been linked, although now many oncologists are not hematologists. Radiation oncology is a subspecialty of radiology that focuses on providing radiation therapy to cancer patients. Also, certain surgeons specialize in the treatment of cancer. Regardless of the branch of medicine to which they belong, cancer specialists work together to ensure a comprehensive approach to treatment for each patient.

Hematology and OncologySections (A-Z)

Anemias Caused by Deficient Erythropoiesis

(See also Approach to the Patient with Anemia .)

Overview of Decreased Erythropoiesis
Iron Deficiency Anemia
Sideroblastic Anemias
Anemia of Chronic Disease
Anemia of Renal Disease
Aplastic Anemia
Pure Red Blood Cell Aplasia
Myelophthisic Anemia
Megaloblastic Macrocytic Anemias
Myelodysplasia and Iron-Transport Deficiency Anemia

Anemias Caused by Hemolysis

At the end of their normal life span (about 120 days), RBCs are removed from the circulation. Hemolysis involves premature destruction and hence a shortened RBC life span ( 120 days). Anemia results when bone marrow production can no longer compensate for the shortened RBC survival; this condition is termed uncompensated hemolytic anemia. If the marrow can compensate, the condition is termed compensated hemolytic anemia.

Overview of Hemolytic Anemia
Autoimmune Hemolytic Anemia
Embden-Meyerhof Pathway Defects
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency
Hemoglobin C Disease
Hemoglobin E Disease
Hemoglobin S-C Disease
Hemoglobin S–Beta-Thalassemia Disease
Hereditary Spherocytosis and Hereditary Elliptocytosis
Paroxysmal Nocturnal Hemoglobinuria (PNH)
Sickle Cell Disease
Stomatocytosis and Anemia Caused by Hypophosphatemia
Thalassemias
Traumatic Hemolytic Anemia

Approach to the Patient With Anemia

Red blood cell (RBC) production (erythropoiesis) takes place in the bone marrow under the control of the hormone erythropoietin (EPO). Juxtaglomerular cells in the kidney produce EPO in response to decreased oxygen delivery (as in anemia and hypoxia) and increased levels of androgens. In addition to EPO, RBC production requires adequate supplies of substrates, mainly iron, vitamin B12, and folate. Vitamin B12 and folate are discussed in Vitamin Deficiency, Dependency, and Toxicity ; iron is discussed in Iron and discussed in Iron Deficiency Anemia . For heme synthesis, see Overview of Porphyrias .

Red Blood Cell Production
Etiology of Anemia
Evaluation of Anemia
Treatment of Anemia

Bleeding Due to Abnormal Blood Vessels

Bleeding may result from abnormalities in

Overview of Vascular Bleeding Disorders
Autoerythrocyte Sensitization
Dysproteinemias Causing Vascular Purpura
Hereditary Hemorrhagic Telangiectasia
Purpura Simplex
Senile Purpura

Coagulation Disorders

Abnormal bleeding can result from disorders of the coagulation system , of platelets , or of blood vessels . Disorders of coagulation can be acquired or hereditary.

Overview of Coagulation Disorders
Disseminated Intravascular Coagulation (DIC)
Hemophilia
Coagulation Disorders Caused by Circulating Anticoagulants
Uncommon Hereditary Coagulation Disorders

Eosinophilic Disorders

Eosinophils are granulocytes derived from the same progenitor cells as monocytes-macrophages, neutrophils, and basophils. They are a component of the innate immune system . Eosinophils have a variety of functions, including

Eosinophil Production and Function
Eosinophilia
Hypereosinophilic Syndrome

Hemostasis

Hemostasis, the arrest of bleeding from an injured blood vessel, requires the combined activity of vascular, platelet, and plasma factors. Regulatory mechanisms counterbalance the tendency of clots to form. Hemostatic abnormalities can lead to excessive bleeding or thrombosis.

Overview of Hemostasis
Excessive Bleeding

Histiocytic Syndromes

The histiocytic syndromes are clinically heterogeneous disorders that result from an abnormal proliferation of histiocytes—either monocyte-macrophages (antigen-processing cells) or dendritic cells (antigen-presenting cells). Classifying these disorders is difficult (see Some Histiocytic Syndromes ) and has changed over time as an understanding of the biology of these cells has evolved. There are other rare histiocytic disorders such as Erdheim-Chester disease, juvenile xanthogranuloma, and others.

Overview of Histiocytic Syndromes
Langerhans Cell Histiocytosis
Hemophagocytic Lymphohistiocytosis (HLH)
Rosai-Dorfman Disease

Iron Overload

(See also Iron Poisoning and Idiopathic Pulmonary Hemosiderosis .)

Overview of Iron Overload
Hemosiderosis
Hereditary Hemochromatosis
Secondary Iron Overload

Leukemias

The leukemias are cancers of the WBCs involving bone marrow, circulating WBCs, and organs such as the spleen and lymph nodes.

Overview of Leukemia
Acute Leukemia Overview
Acute Lymphocytic Leukemia (ALL)
Acute Myelogenous Leukemia (AML)
Chronic Lymphocytic Leukemia (CLL)
Chronic Myelogenous Leukemia (CML)
Myelodysplastic Syndrome

Leukopenias

Leukopenia is a reduction in the circulating WBC count to 4000/ μ L. It is usually characterized by a reduced number of circulating neutrophils, although a reduced number of lymphocytes, monocytes, eosinophils, or basophils may also contribute. Thus, immune function is generally decreased.

Overview of Leukopenias
Lymphocytopenia
Monocytopenia
Neutropenia

Lymphomas

Lymphomas are a heterogeneous group of tumors arising in the reticuloendothelial and lymphatic systems. The major types are Hodgkin lymphoma and non-Hodgkin lymphoma (NHL— Comparison of Hodgkin Lymphoma and Non-Hodgkin Lymphoma ).

Overview of Lymphoma
Hodgkin Lymphoma
Non-Hodgkin Lymphomas
Burkitt Lymphoma
Mycosis Fungoides

Myeloproliferative Disorders

Myeloproliferative disorders are abnormal proliferations of bone marrow stem cells, which can manifest as increased platelets, RBCs, or WBCs in the circulation and sometimes as increased fibrosis in the bone marrow with consequent extramedullary hematopoiesis (cell production outside the marrow). Based on these abnormalities, they are classified as

Overview of Myeloproliferative Disorders
Essential Thrombocythemia
Reactive Thrombocytosis (Secondary Thrombocythemia)
Primary Myelofibrosis
Polycythemia Vera
Secondary Erythrocytosis

Overview of Cancer

Cancer is an unregulated proliferation of cells. Its prominent properties are a lack of differentiation of cells, local invasion of adjoining tissue, and, often, metastasis (spread to distant sites through the bloodstream or the lymphatic system). The immune system likely plays a significant role in eliminating early cancers or premalignant cells because immunodeficiency states are associated with an increased incidence of various kinds of cancer, particularly those associated with viral infection, and tumors arising in the lymphatic system and the skin.

Introduction to Overview of Cancer
Cellular and Molecular Basis of Cancer
Cancer Diagnosis
Cancer Screening
Clinical Sequelae of Cancer
Metastatic Carcinoma of Unknown Primary Origin
Paraneoplastic Syndromes

Plasma Cell Disorders

Plasma cell disorders are a diverse group of disorders of unknown etiology characterized by

Overview of Plasma Cell Disorders
Heavy Chain Diseases
Macroglobulinemia
Monoclonal Gammopathy of Undetermined Significance (MGUS)
Multiple Myeloma

Principles of Cancer Therapy

Curing cancer requires eliminating all cancer cells. The major modalities of therapy are

Overview of Cancer Therapy
Modalities of Cancer Therapy
Management of Adverse Effects of Cancer Therapy
Cachexia in Cancer
Incurable Cancer

Spleen Disorders

By structure and function, the spleen is like 2 organs. The white pulp, consisting of periarterial lymphatic sheaths and germinal centers, acts as an immune organ. The red pulp, consisting of macrophages and granulocytes lining vascular spaces (the cords and sinusoids), acts as a phagocytic organ.

Overview of the Spleen
Splenomegaly
Hypersplenism

Thrombocytopenia and Platelet Dysfunction

Platelets are cell fragments that function in the clotting system. Thrombopoietin helps control the number of circulating platelets by stimulating the bone marrow to produce megakaryocytes, which in turn shed platelets from their cytoplasm. Thrombopoietin is produced in the liver at a constant rate and its circulating level is determined by the extent to which circulating platelets are cleared, and possibly by bone marrow megakaryocytes. Platelets circulate for 7 to 10 days. About one third are always transiently sequestered in the spleen.

Overview of Platelet Disorders
Acquired Platelet Dysfunction
Hereditary Intrinsic Platelet Disorders
Immune Thrombocytopenia (ITP)
Thrombocytopenia Due to Splenic Sequestration
Thrombocytopenia: Other Causes
Thrombotic Thrombocytopenic Purpura (TTP) and Hemolytic-Uremic Syndrome (HUS)
Von Willebrand Disease

Thrombotic Disorders

In healthy people, homeostatic balance exists between procoagulant (clotting) forces and anticoagulant and fibrinolytic forces. Numerous genetic, acquired, and environmental factors can tip the balance in favor of coagulation, leading to the pathologic formation of thrombi in veins (eg, deep venous thrombosis [DVT]), arteries (eg, myocardial infarction, ischemic stroke), or cardiac chambers. Thrombi can obstruct blood flow at the site of formation or detach and embolize to block a distant blood vessel (eg, pulmonary embolism, embolic stroke).

Overview of Thrombotic Disorders
Antiphospholipid Antibody Syndrome (APS)
Antithrombin Deficiency
Hyperhomocysteinemia
Factor V Resistance to Activated Protein C (APC)
Protein C Deficiency
Protein S Deficiency
Protein Z Deficiency
Prothrombin (Factor II) 20210 Gene Mutation

Transfusion Medicine

More than 25 million units of blood components are transfused yearly in the US, from about 9 million volunteer donors. Although transfusion is probably safer than ever, risk (and the public’s perception of risk) mandates informed consent whenever practical.

Blood Collection
Blood Products
Technique of Transfusion
Complications of Transfusion
Therapeutic Apheresis

Tumor Immunology

Many tumor cells produce antigens, which may be released in the bloodstream or remain on the cell surface. Antigens have been identified in most of the human cancers, including Burkitt lymphoma, neuroblastoma, malignant melanoma, osteosarcoma, renal cell carcinoma, breast carcinoma, prostate cancer, lung carcinomas, and colon cancer. A key role of the immune system is detection of these antigens to permit subsequent targeting for eradication. However, despite their foreign structure, the immune response to tumor antigens varies and is often insufficient to prevent tumor growth.

Tumor Antigens
Host Response to Tumors
Tumor Immunodiagnosis
Immunotherapy of Cancer

View by:

Also of Interest

Test your knowledge

Which of the following is a correct statement about classical Hodgkin lymphoma?

Chemotherapy with or without radiation therapy achieves cure in 50% of patients. Disease-free survival 5 yr after therapy is considered a cure. Relapse within 1 yr after therapy is reversible with rescue therapy in most cases. Female patients are more likely to experience relapse.