The signs and symptoms of non-Hodgkin's lymphoma vary depending upon its location within the body. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and feeling tired. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing while others are fast growing. Enlarged lymph nodes may cause lumps to be felt under the skin when they are close to the surface of the body. Lymphomas in the skin may also result in lumps, which are commonly itchy, red or purple. Lymphomas in the brain can cause weakness, seizures, problems with thinking and personality changes.

Patients with Hodgkin's lymphoma may present with the following symptoms:

- Lymph nodes: the most common symptom of Hodgkin's is the painless enlargement of one or more lymph nodes, or lymphadenopathy. The nodes may also feel rubbery and swollen when examined. The nodes of the neck and shoulders (cervical and supraclavicular) are most frequently involved (80–90% of the time, on average). The lymph nodes of the chest are often affected, and these may be noticed on a chest radiograph.

- Itchy skin

- Night sweats

- Unexplained weight loss

- Splenomegaly: enlargement of the spleen occurs in about 30% of people with Hodgkin's lymphoma. The enlargement, however, is seldom massive, and the size of the spleen may fluctuate during the course of treatment.

- Hepatomegaly: enlargement of the liver, due to liver involvement, is present in about 5% of cases.

- Hepatosplenomegaly: the enlargement of both the liver and spleen caused by the same disease.

- Pain following alcohol consumption: classically, involved nodes are painful after alcohol consumption, though this phenomenon is very uncommon, occurring in only two to three percent of people with Hodgkin's lymphoma, thus having a low sensitivity. On the other hand, its positive predictive value is high enough for it to be regarded as a pathognomonic sign of Hodgkin lymphoma. The pain typically has an onset within minutes after ingesting alcohol, and is usually felt as coming from the vicinity where there is an involved lymph node. The pain has been described as either sharp and stabbing or dull and aching.

- Back pain: nonspecific back pain (pain that cannot be localised or its cause determined by examination or scanning techniques) has been reported in some cases of Hodgkin's lymphoma. The lower back is most often affected.

- Red-coloured patches on the skin, easy bleeding and petechiae due to low platelet count (as a result of bone marrow infiltration, increased trapping in the spleen etc.—i.e. decreased production, increased removal)

- Systemic symptoms: about one-third of patients with Hodgkin's disease may also present with systemic symptoms, including low-grade fever; night sweats; unexplained weight loss of at least 10% of the patient's total body mass in six months or less, itchy skin (pruritus) due to increased levels of eosinophils in the bloodstream; or fatigue (lassitude). Systemic symptoms such as fever, night sweats, and weight loss are known as B symptoms; thus, presence of fever, weight loss, and night sweats indicate that the patient's stage is, for example, 2B instead of 2A.

- Cyclical fever: patients may also present with a cyclical high-grade fever known as the Pel-Ebstein fever, or more simply "P-E fever". However, there is debate as to whether the P-E fever truly exists.

- Nephrotic syndrome can occur in individuals with Hodgkin's lymphoma and is most commonly caused by minimal change disease.

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.

- 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:

- Loss of appetite or anorexia

- Fatigue

- Respiratory distress or dyspnea

- Itching

Lymphomas in the strict sense are any neoplasms of the lymphatic tissues ("" + "") . The main classes are malignant neoplasms (that is, cancers) of the lymphocytes, a type of white blood cell that belongs to both the lymph and the blood and pervades both. Thus, lymphomas and leukemias are both tumors of the hematopoietic and lymphoid tissues, and as lymphoproliferative disorders, lymphomas and lymphoid leukemias are closely related, to the point that some of them are unitary disease entities that can be called by either name (for example, adult T-cell leukemia/lymphoma).

Several classification systems have existed for lymphoma, which use histological and other findings to divide lymphoma into different categories. The classification of a lymphoma can affect treatment and prognosis. Classification systems generally classify lymphoma according to:

- Whether or not it is a Hodgkin lymphoma

- Whether the cell that is replicating is a T cell or B cell

- The site from which the cell arises

Lymphoma can also spread to the central nervous system, often around the brain in the meninges, known as lymphomatous meningitis (LM).

The many different forms of lymphoma probably have different causes. These possible causes and associations with at least some forms of NHL include the following:

- Infectious agents:

- Epstein-Barr virus: associated with Burkitt's lymphoma, Hodgkin's lymphoma, follicular dendritic cell sarcoma, extranodal NK-T-cell lymphoma

- Human T-cell leukemia virus: associated with adult T-cell lymphoma

- Helicobacter pylori: associated with gastric lymphoma

- HHV-8: associated with primary effusion lymphoma, multicentric Castleman disease

- Hepatitis C virus: associated with splenic marginal zone lymphoma, lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma

- HIV infection

- Some chemicals, like polychlorinated biphenyls (PCBs), diphenylhydantoin, dioxin, and phenoxy herbicides.

- Medical treatments, like radiation therapy and chemotherapy

- Genetic diseases, like Klinefelter's syndrome, Chédiak-Higashi syndrome, ataxia telangiectasia syndrome

- Autoimmune diseases, like Sjögren’s syndrome, celiac disease, rheumatoid arthritis, and systemic lupus erythematosus.

Hodgkin's lymphoma (HL) is a type of lymphoma, which is generally believed to result from white blood cells of the lymphocyte kind. Symptoms may include fever, night sweats, and weight loss. Often there will be non-painful enlarged lymph nodes in the neck, under the arm, or in the groin. Those affected may feel tired or be itchy.

About half of cases of Hodgkin's lymphoma are due to Epstein–Barr virus (EBV). Other risk factors include a family history of the condition and having HIV/AIDS. There are two major types of Hodgkin lymphoma: classical Hodgkin lymphoma and nodular lymphocyte-predominant Hodgkin lymphoma. Diagnosis is by finding Hodgkin's cells such as multinucleated Reed–Sternberg cells (RS cells) in lymph nodes.

Hodgkin lymphoma may be treated with chemotherapy, radiation therapy, and stem cell transplant. The choice of treatment often depends on how advanced the cancer has become and whether or not it has favorable features. In early disease, a cure is often possible. The percentage of people who survive five years in the United States is 86%. For those under the age of 20, rates of survival are 97%. Radiation and some chemotherapy drugs, however, increase the risk of other cancers, heart disease, or lung disease over the subsequent decades.

In 2015 about 574,000 people had Hodgkin's lymphoma, and 23,900 died. In the United States, 0.2% of people are affected at some point in their life. The most common age of diagnosis is between 20 and 40 years old. It was named after the English physician Thomas Hodgkin, who first described the condition in 1832.

The B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph nodes. They develop more frequently in older adults and in immunocompromised individuals.

B-cell lymphomas include both Hodgkin's lymphomas and most non-Hodgkin lymphomas. They are typically divided into low and high grade, typically corresponding to indolent (slow-growing) lymphomas and aggressive lymphomas, respectively. As a generalisation, indolent lymphomas respond to treatment and are kept under control (in remission) with long-term survival of many years, but are not cured. Aggressive lymphomas usually require intensive treatments, with some having a good prospect for a permanent cure.

Prognosis and treatment depends on the specific type of lymphoma as well as the stage and grade. Treatment includes radiation and chemotherapy. Early-stage indolent B-cell lymphomas can often be treated with radiation alone, with long-term non-recurrence. Early-stage aggressive disease is treated with chemotherapy and often radiation, with a 70-90% cure rate. Late-stage indolent lymphomas are sometimes left untreated and monitored until they progress. Late-stage aggressive disease is treated with chemotherapy, with cure rates of over 70%.

There are numerous kinds of lymphomas involving B cells. The most commonly used classification system is the WHO classification, a convergence of more than one, older classification systems.

The clinical presentation varies according to the type of ALCL. Two of the ALCL subtypes are systemic lymphomas, in that they usually present with enlarged lymph nodes in multiple regions of the body, or with tumors outside the lymph nodes (extranodal) such as bone, intestine, muscle, liver, or spleen. These 2 subtypes usually associate with weight loss, fevers and night sweats, and can be lethal if left untreated without chemotherapy. The third type of ALCL is so-called cutaneous ALCL, and is a tumor that presents in the skin as ulcers that may persist, or occasionally may involute spontaneously, and commonly recur. This type of ALCL usually manifests in different regions of the body and may extend to regional lymph nodes, i.e., an axillary lymph node if the ALCL presents in the arm.

A rare subtype of ALCL has been identified in a few women who have silicone breast implants (protheses) as a result of breast reconstruction after a diagnosis of breast cancer. The tumor initially manifests with swelling of the breast due to fluid accumulation around the implant. The disease may progress to invade the tissue surrounding the capsule, and if left untreated may progress to the axillary lymph nodes.

It typically presents at a late stage and is often associated with systemic symptoms ("B symptoms").

General signs and symptoms include depression, fever, weight loss, loss of appetite, loss of hair or fur and vomiting. Lymphoma is the most common cancerous cause of hypercalcemia (high blood calcium levels) in dogs. It can lead to the above signs and symptoms plus increased water drinking, increased urination, and cardiac arrhythmias. Hypercalcemia in these cases is caused by secretion of parathyroid hormone-related protein.

Multicentric lymphoma presents as painless enlargement of the peripheral lymph nodes. This is seen in areas such as under the jaw, the armpits, the groin, and behind the knees. Enlargement of the liver and spleen causes the abdomen to distend. Mediastinal lymphoma can cause fluid to collect around the lungs, leading to coughing and difficulty breathing. Hypercalcemia is most commonly associated with this type.

Gastrointestinal lymphoma causes vomiting, diarrhea, and melena (digested blood in the stool). Low serum albumin levels and hypercalcemia can also occur.

Lymphoma of the skin is an uncommon occurrence. The epitheliotropic form typically appears as itchy inflammation of the skin progressing to nodules and plaques.

The non-epitheliotropic form can have a wide variety of appearances, from a single lump to large areas of bruised, ulcerated, hairless skin. The epitheliotropic form must be differentiated from similar appearing conditions such as pemphigus vulgaris, bullous pemphigoid, and lupus erythematosus.

Signs for lymphoma in other sites depend on the location. Central nervous system involvement can cause seizures or paralysis. Eye involvement, seen in 20 to 25 percent of cases, can lead to glaucoma, uveitis, bleeding within the eye, retinal detachment, and blindness. Lymphoma in the bone marrow causes anemia, low platelet count, and low white blood cell count.

Cats that develop lymphoma are much more likely to develop more severe symptoms than dogs. Whereas dogs often appear healthy initially except for swollen lymph nodes, cats will often be physically ill. The symptoms correspond closely to the location of the lymphoma. The most common sites for alimentary (gastrointestinal) lymphoma are, in decreasing frequency, the small intestine, the stomach, the junction of the ileum, cecum, and colon. Cats with the alimentary form of lymphoma often present with weight loss, rough hair coat, loss of appetite, vomiting and diarrhea, although vomiting and diarrhea are commonly absent as symptoms. The tumor can also cause life-threatening blockage of the intestine. Cats with the mediastinal form often have respiratory distress and fluid in the thoracic cavity. If lymphoma develops in the kidney, the cat may have increased water consumption and increased urination. Lymphoma of the kidney presents as bilateral kidney enlargement and failure. If the lymphoma is located in the nose, the cat may have discharge from the nose and facial swelling. Lymphoma of the heart causes congestive heart failure, pericardial effusion, and cardiac arrhythmias. Ocular lymphoma in cats often presents as anterior uveitis (inflammation of the inside of the eye). Cats who are also infected with FeLV often present with pale mucous membranes due to anemia. Anemia is a common problem in all cats with lymphoma, but hypercalcemia is rare.

Diagnosis is similar to dogs, except cats should be tested for FeLV and FIV. It is important to differentiate the alimentary form of lymphoma from inflammatory bowel disease because the signs are so similar in cats. A biopsy is necessary to do this. One approach to differentiate inflammatory bowel disease from is to test the infiltrating lymphocytes for their monoclonal origin in lymphomas.

Diagnosis usually occurs at an early stage of disease progression.

Symptoms of Richter’s transformation in a CLL patient include fever (without infection), an elevated serum levels of lactate dehydrogenase, and rapidly enlarging lymph nodes. While about 8% of all CLL patients will have elevated levels of serum lactate dehydrogenase (LDH), more than 50% of CLL patients with Richter's transformation will have elevated LDH levels.

Richter's can appear suddenly, even in patients who were in remission.

Ann Arbor staging is used to classify tumors and symptoms. Stage IV disease is very rare.

The prognosis is generally poor. The "RS score" (Richter syndrome score), which is an estimate of the patient's prognosis, is based on the patient's performance status, LDH, platelet count, the size of the lymphoma tumors, and the number of prior therapies already received. Overall, the median survival is between five and eight months. Untreated, RS is invariably fatal.

The Hodgkin's lymphoma variant of Richter's carries a better prognosis than the predominant diffuse large B-cell lymphoma type, but a worse prognosis than a "de novo" case of Hodgkin's.

Anaplastic large-cell lymphoma (ALCL) is a type of non-Hodgkin lymphoma involving aberrant T cells or null lymphocytes. It is described in detail in the "Classification of Tumours of the Haematopoietic and Lymphoid Tissues" edited by experts of the World Health Organisation (WHO). The term anaplastic large cell lymphoma (ALCL) encompasses at least 4 different clinical entities, all sharing the same name, and histologically have also in common the presence of large pleomorphic cells that express CD30 and T-cell markers. Two types of ALCL present as systemic disease and are considered as aggressive lymphomas, while two types present as localized disease and may progress locally.

Its name derives from anaplasia and large-cell lymphoma.

Castleman disease, also known as giant lymph node hyperplasia, lymphoid hamartoma, or angiofollicular lymph node hyperplasia, is a group of uncommon lymphoproliferative disorders that share common lymph node histological features. The disease is named after Benjamin Castleman.

Castleman's disease has two main forms: It may be localized to a single lymph node (unicentric) or occur systemically (multicentric).

The unicentric form can usually be cured by surgically removing the lymph node, with a 10-year survival of 95%.

Multicentric Castleman disease (MCD) involves hyperactivation of the immune system, excessive release of proinflammatory chemicals (cytokines), proliferation of immune cells (B cells and T cells), and multiple organ system dysfunction. Castleman disease must be distinguished from other disorders that can demonstrate "Castleman-like" lymph node features, including reactive lymph node hyperplasia, autoimmune disorders, and malignancies. Multicentric Castleman's disease is associated with lymphoma and Kaposi's sarcoma.

Unicentric Castleman disease involves "Castleman-like" lymph node changes at only a single site. Enlarged lymph nodes in the chest can press on the windpipe (trachea) or smaller breathing tubes going into the lungs (bronchi), causing breathing problems. If the enlarged nodes are in the abdomen, the person might have pain, a feeling of fullness, or trouble eating. In at least 90% of cases, removal of the enlarged node is curative with no further complications.

Multicentric Castleman disease (MCD) involves "Castleman-like" lymph node changes at multiple sites and patients often demonstrate intense episodes of systemic inflammatory symptoms, polyclonal/reactive lymphocyte and plasma cell proliferation, autoimmune manifestations, and multiple organ system impairment.

- HHV-8-associated Multicentric Castleman disease HHV-8, also called KSHV, is a gammaherpesvirus that is responsible for causing approximately 50% of MCD cases by driving excessive cytokine release secondary to the expression of the virus-encoded cytokine, vIL-6. These cases are referred to as HHV-8-associated MCD and all demonstrate "plasmablastic" lymph node features. HHV-8 also causes Kaposi's sarcoma and primary effusion lymphoma. Most cases of HHV-8-associated MCD are also HIV positive, because HIV and other causes of immunosuppression prevent the body from being able to control HHV-8 viral replication. This is most likely due to expression of the virus

- HHV-8-negative Multicentric Castleman disease The cause for immune activation that is responsible for the other 50% of MCD cases is unknown. These cases are referred to as idiopathic MCD. Idiopathic MCD can demonstrate hyaline vascular, plasmacytic, or mixed lymph node features.

People affected by T-cell prolymphocytic leukemia typically have systemic disease at presentation, including enlargement of the liver and spleen, widespread enlargement of the lymph nodes, and skin infiltrates.

Due to the systemic nature of this disease, leukemic cells can be found in peripheral blood, lymph nodes, bone marrow, spleen, liver, and skin. A high lymphocyte count (> 100 x 10/L) along with low amounts of red blood cells and platelets in the blood are common findings. HTLV-1 serologies are negative, and serum immunoglobins are within normal limits with no paraproteins present.

It is postulated that the originating cell line for this disease is a mature (post-thymic) T-cell.

Most people are diagnosed without symptoms as the result of a routine blood test that shows a high white blood cell count. Less commonly, CLL may present with enlarged lymph nodes without a high white blood cell count or no evidence of the disease in the blood. This is referred to as small lymphocytic lymphoma. In some individuals, the disease comes to light only after the cancerous cells overwhelm the bone marrow resulting in anemia producing tiredness or weakness.

Signs and symptoms of WM include weakness, fatigue, weight loss, and chronic oozing of blood from the nose and gums. Peripheral neuropathy occurs in 10% of patients. Enlargement of the lymph nodes, spleen, and/or liver are present in 30–40% of cases. Other possible signs and symptoms include blurring or loss of vision, headache, and (rarely) stroke or coma.

Chronic lymphoid leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell). Early on there is typically no symptoms. Latter non-painful lymph nodes swelling, feeling tired, fever, or weight loss for no clear reason may occur. Enlargement of the spleen and anemia may also occur. It typically worsens gradually.

Risk factors include having a family history of the disease. Agent Orange and certain insecticides might also be a risk. CLL results in the build up of B cell lymphocytes in the bone marrow, lymph nodes, and blood. These cells do not function well and crowd out healthy blood cells. It is divided into two main types those with a mutated IGHV gene and those without. Diagnosis is typically based on blood tests finding high numbers of mature lymphocytes and smudge cells.

Management of early disease is generally with watchful waiting. Infections should more readily be treated with antibiotics. In those with significant symptoms chemotherapy or immunotherapy may be used. The medications fludarabine, cyclophosphamide, and rituximab are typically the initial treatment in those who are otherwise healthy.

CLL affected about 904,000 people globally in 2015 and resulted in 60,700 deaths. The disease most common occurs in people over the age of 50. Males are affected more often than females. It is much less common in people from Asia. Five-year survival following diagnosis is approximately 83% in the United States. It represents less than 1% of deaths from cancer.

Tumors of the hematopoietic and lymphoid tissues or haematopoietic and lymphoid malignancies are tumors that affect the blood, bone marrow, lymph, and lymphatic system. As those elements are all intimately connected through both the circulatory system and the immune system, a disease affecting one will often affect the others as well, making myeloproliferation and lymphoproliferation (and thus the leukemias and the lymphomas) closely related and often overlapping problems.

While uncommon in solid tumors, chromosomal translocations are a common cause of these diseases. This commonly leads to a different approach in diagnosis and treatment of haematological malignancies.

Haematological malignancies are malignant neoplasms ("cancer"), and they are generally treated by specialists in hematology and/or oncology. In some centers "Haematology/oncology" is a single subspecialty of internal medicine while in others they are considered separate divisions (there are also surgical and radiation oncologists). Not all haematological disorders are malignant ("cancerous"); these other blood conditions may also be managed by a hematologist.

Hematological malignancies may derive from either of the two major blood cell lineages: myeloid and lymphoid cell lines. The myeloid cell line normally produces granulocytes, erythrocytes, thrombocytes, macrophages and mast cells; the lymphoid cell line produces B, T, NK and plasma cells. Lymphomas, lymphocytic leukemias, and myeloma are from the lymphoid line, while acute and chronic myelogenous leukemia, myelodysplastic syndromes and myeloproliferative diseases are myeloid in origin.

A subgroup of them are more severe and are known as haematological malignancies (American spelling hematological malignancies) or blood cancer. They may also be referred to as liquid tumors.

Under older classification systems, the following names were used: