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.

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

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.

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 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").

Currently, Burkitt lymphoma can be divided into three main clinical variants: the endemic, the sporadic, and the immunodeficiency-associated variants.

- The endemic variant (also called "African variant") most commonly occurs in children living in malaria endemic regions of the world (e.g., equatorial Africa, Brazil, and Papua New Guinea). Epstein-Barr virus (EBV) infection is found in nearly all patients. Chronic malaria is believed to reduce resistance to EBV, allowing it to take hold. The disease characteristically involves the jaw or other facial bone, distal ileum, cecum, ovaries, kidney, or breast.

- The sporadic type of Burkitt lymphoma (also known as "non-African") is the most common variant found in places where malaria is not holoendemic. The tumor cells have a similar appearance to the cancer cells of classical endemic Burkitt lymphoma. Sporadic lymphomas are rarely associated with the Epstein–Barr virus. Non-Hodgkin lymphoma, which includes Burkitt's, accounts for 30–50% of childhood lymphoma. The jaw is less commonly involved, compared to the endemic variant. The ileocecal region is the common site of involvement.

- Immunodeficiency-associated Burkitt lymphoma is usually associated with HIV infection or occurs in the setting of post-transplant patients who are taking immunosuppressive drugs. Burkitt lymphoma can be one of the diseases associated with the initial manifestation of AIDS.

By morphology (i.e., microscopic appearance) or immunophenotype, it is almost impossible to differentiate these three clinical variants. Immunodeficiency-associated Burkitt lymphoma may demonstrate more plasmacytic appearance or more pleomorphism, but these features are not specific.

At diagnosis, patients typically are in their 60s and present to their physician with advanced disease. About half have either fever, night sweats, or unexplained weight loss (over 10% of body weight). Enlarged lymph nodes (for example, a "bump" on the neck, armpits or groin) or splenomegaly are usually present. Bone marrow, liver and GI tract involvement occurs relatively early in the course of the disease.

The presentation depends if it is mycosis fungoides or Sézary syndrome the most common, though not the only types.

Among the symptoms for the aforementioned types are:lymphadenopathy, hepatosplenomegaly, and non-specific dermatitis.

A primary CNS lymphoma usually presents with seizure, headache, cranial nerve findings, altered mental status, or other focal neurological deficits typical of a mass effect. Systemic symptoms may include fever, night sweats, or weight loss.Other symptoms include

- diplopia

- dysphagia

- vertigo

- monocular vision loss

- progressive dementia or stupor in patients with a nonfocal neurologic exam and minimal abnormalities on MRI (more common in AIDS patients)

- facial hypoesthesia

A point-based algorithm for the diagnosis for early forms of cutaneous T cell lymphoma was proposed by The International Society for Cutaneous Lymphomas in 2005.

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.

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.

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.

Burkitt lymphoma is a cancer of the lymphatic system, particularly B lymphocytes found in the germinal center. It is named after Denis Parsons Burkitt, a surgeon who first described the disease in 1958 while working in equatorial Africa.

Patients usually present with constitutional symptoms (malaise, weight loss, fatigue), and hepatosplenomegaly is commonly found on physical exam. Lymphadenopathy is also found to a lesser extent. Due to the aggressive nature of the disease, patients may initially present at a more advanced stage, with coagulopathies, hemophagocytic syndrome, and multi-organ failure.

Mantle cell lymphoma (MCL) is a type of non-Hodgkin's lymphoma (NHL), comprising about 6% of NHL cases. There are only about 15,000 patients presently in the U.S.

MCL is a subtype of B-cell lymphoma, due to CD5 positive antigen-naive pregerminal center B-cell within the mantle zone that surrounds normal germinal center follicles. MCL cells generally over-express cyclin D1 due to a t(11:14) chromosomal translocation in the DNA. Specifically, the translocation is at t(11;14)(q13;q32).

Diagnosis usually occurs at an early stage of disease progression.

Diffuse large B-cell lymphoma encompasses a biologically and clinically diverse set of diseases, many of which cannot be separated from one another by well-defined and widely accepted criteria. The World Health Organization (WHO) classification system defines more than a dozen subtypes, each of which can be differentiated based on the location of the tumor, the presence of other cells within the tumor (such as T cells), and whether the patient has certain other illnesses related to DLBCL. One of these well-defined groupings of particular note is "primary mediastinal (thymic) large B cell lymphoma", which arises within the thymus or mediastinal lymph nodes.

In some cases, a tumor may share many features with both DLBCL and Burkitt's lymphoma. In these situations, the tumor is classified as simply “B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma”. A similar situation can arise between DLBCL and Hodgkin's lymphoma; the tumor is then classified as “B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Hodgkin’s lymphoma”.

When a case of DLBCL does not conform to any of these subtypes, and is also not considered unclassifiable, then it is classified as “diffuse large B-cell lymphoma, not otherwise specified” (DLBCL, NOS). The majority of DLBCL cases fall into this category. Much research has been devoted to separating this still-heterogeneous group; such distinctions are usually made along lines of cellular morphology, gene expression, and immunohistochemical properties.

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

The T-cell lymphomas are four types of lymphoma that affect T cells. These account for about one in ten cases of non-Hodgkin lymphoma.

They can be associated with Epstein Barr virus and Human T-cell leukemia virus-1.

A primary central nervous system lymphoma (PCNSL), also known as microglioma and primary brain lymphoma, is a primary intracranial tumor appearing mostly in patients with severe immunodeficiency (typically patients with AIDS). PCNSLs represent around 20% of all cases of lymphomas in HIV infections (other types are Burkitt's lymphomas and immunoblastic lymphomas). Primary CNS lymphoma is highly associated with Epstein-Barr virus (EBV) infection (> 90%) in immunodeficient patients (such as those with AIDS and those immunosuppressed), and does not have a predilection for any particular age group. Mean CD4+ count at time of diagnosis is ~50/uL. In immunocompromised patients, prognosis is usually poor. In immunocompetent patients (that is, patients who do not have AIDS or some other immunodeficiency), there is rarely an association with EBV infection or other DNA viruses. In the immunocompetent population, PCNSLs typically appear in older patients in their 50's and 60's. Importantly, the incidence of PCNSL in the immunocompetent population has been reported to have increased more than 10-fold from 2.5 cases to 30 cases per 10 million population. The cause for the increase in incidence of this disease in the immunocompetent population is unknown.

Richter's syndrome (RS), also known as Richter's transformation, is a transformation which occurs in about 5-10% of B cell chronic lymphocytic leukemia (CLL) and hairy cell leukemia into a fast-growing diffuse large B cell lymphoma, a variety of non-Hodgkin lymphoma which is refractory to treatment and carries a bad prognosis. There is also a less common variant in which the CLL changes into a Hodgkin's lymphoma. Rarely, transformations to a form of myeloid leukemia have been observed. These extraordinarily rare transformations carry a very poor prognosis.

Richter's transformation affects about 5% of CLL patients at some point during their lives.

There are two main types of intraocular lymphomas: primary central nervous system involvement (PCNSL) and primary central nervous system with ocular involvement (PCNSLO). The difference between PCNSL and PCNSLO is that PNSCL involves the central nervous system, while PCNSLO does not. 56-86% of orbital lymphomas are classified PCNSL and 15-25% are classified PCNSLO.

PCNSLO is common in people who are severely immunosuppressed.

Symptoms of this form of ocular lymphoma include painless decreased vision, sensitivity to light, a red eye, and floaters. Diagnosis is difficult due to its gradual onset and the fact that the symptoms are the same as other diseases.

PCNSLO is usually bilateral, but sometimes grows unevenly. Like other metastatic tumors of the eye, it is usually confined to the choroid.