Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). The name typically refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and constantly feeling tired. The enlarged lymph nodes are usually painless. The sweats are most common at night.
Many subtypes of lymphomas are known. The two main categories of lymphomas are the non-Hodgkin lymphoma (NHL) (90% of cases) and Hodgkin lymphoma (HL) (10%). Lymphomas, leukemias and myelomas are a part of the broader group of tumors of the hematopoietic and lymphoid tissues.
Risk factors for Hodgkin lymphoma include infection with Epstein–Barr virus and a history of the disease in the family. Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymphotropic virus, immunosuppressant medications, and some pesticides. In 2014, the International Agency for Research on Cancer updated its classification of trichloroethylene to Group 1, indicating that sufficient evidence exists that it causes cancer of the kidney in humans as well as some evidence of cancer of the liver and non-Hodgkin's lymphoma. Eating large amounts of red meat and tobacco smoking may also increase the risk. Diagnosis, if enlarged lymph nodes are present, is usually by lymph node biopsy. Blood, urine, and bone marrow testing may also be useful in the diagnosis. Medical imaging may then be done to determine if and where the cancer has spread. Lymphoma most often spreads to the lungs, liver, and brain.
Treatment may involve one or more of the following: chemotherapy, radiation therapy, proton therapy, targeted therapy, and surgery. In some non-Hodgkin lymphomas, an increased amount of protein produced by the lymphoma cells causes the blood to become so thick that plasmapheresis is performed to remove the protein. Watchful waiting may be appropriate for certain types. The outcome depends on the subtype with some being curable and treatment prolonging survival in most. The five-year survival rate in the United States for all Hodgkin lymphoma subtypes is 85%, while that for non-Hodgkin lymphomas is 69%. Worldwide, lymphomas developed in 566,000 people in 2012 and caused 305,000 deaths. They make up 3–4% of all cancers, making them as a group the seventh-most common form. In children, they are the third-most common cancer. They occur more often in the developed world than the developing world.
Signs and symptoms
Lymphoma may present with certain nonspecific symptoms; if the symptoms are persistent, an evaluation to determine their cause, including possible lymphoma, should be undertaken. Lymphadenopathy or swelling of lymph nodes, is the primary presentation in lymphoma. It is generally painless. B symptoms (systemic symptoms) – can be associated with both Hodgkin lymphoma and non-Hodgkin lymphoma. They consist of: Fever Night sweats Weight loss Other symptoms: Anemia, bleeding, increased susceptibility to infections Loss of appetite or anorexia Fatigue Respiratory distress or dyspnea Itching
Mouth
Asymptomatic soft swelling, which may or may not be ulcerated, is primarily seen on the tonsils, buccal mucosa, palate, gums, salivary glands, tongue, the floor of the mouth, and retromolar region.
Diagnosis
Lymphoma is definitively diagnosed by a lymph-node biopsy, meaning a partial or total excision of a lymph node examined under the microscope. This examination reveals histopathological features that may indicate lymphoma. After lymphoma is diagnosed, a variety of tests may be carried out to look for specific features characteristic of different types of lymphoma. These include: Immunophenotyping Flow cytometry Fluorescence in situ hybridization testing
Classification
According to the World Health Organization (WHO), lymphoma classification should reflect in which lymphocyte population the neoplasm arises. Thus, neoplasms that arise from precursor lymphoid cells are distinguished from those that arise from mature lymphoid cells. Most mature lymphoid neoplasms comprise the non-Hodgkin lymphomas. Historically, mature histiocytic and dendritic cell (HDC) neoplasms have been considered mature lymphoid neoplasms, since these often involve lymphoid tissue.
Lymphoma can also spread to the central nervous system, often around the brain in the meninges, known as lymphomatous meningitis (LM).