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

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.

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%.

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 typical clinical finding in a patient with hepatosplenic T-cell lymphoma is hepatosplenomegaly.

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.

Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS), is a subtype of peripheral T-cell lymphoma. Peripheral T-cell lymphoma (PTCL) is defined as a diverse group of aggressive lymphomas that develop from mature-stage white blood cells called T-cells and natural killer cells (NK cells) (see figure for an overview of PTCL subtypes). PTCL is a type of non-Hodgkin's lymphoma (NHL). NHL affects two particular types of white blood cells: B-cells and T-cells. PTCL specifically affects T-cells, and results when T-cells develop and grow abnormally.

PTCL-NOS, the most common subtype of PTCL, is aggressive and predominantly nodal. There are two morphologic variants: the T-zone lymphoma variant and the lymphoepithelioid cell variant.

- T-zone lymphoma is so named for its involvement in a specific area of the lymph node that consists of a dense accumulation of T-cells.

- Lympho-epithelioid lymphoma, also called Lennert's lymphoma, is rare and generally affects older individuals.

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 spleen and liver are always involved, with bone marrow involvement frequently present. Nodal involvement is exceedingly rare.

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 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.

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.

Peripheral T-cell lymphoma refers to a group of T-cell lymphomas that develop away from the thymus.

Examples include:

- Cutaneous T-cell lymphomas

- Angioimmunoblastic T-cell lymphoma

- Extranodal natural killer/T-cell lymphoma, nasal type

- Enteropathy type T-cell lymphoma

- Subcutaneous panniculitis-like T-cell lymphoma

- Anaplastic large cell lymphoma

- Peripheral T-cell lymphoma-Not-Otherwise-Specified

In ICD-10, cutaneous T-cell lymphomas are classified separately.

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").

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).

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.

The four classes are:

- Extranodal T cell lymphoma

- Cutaneous T cell lymphomas: Sézary syndrome and Mycosis fungoides

- Anaplastic large cell lymphoma

- Angioimmunoblastic T cell lymphoma

More information on various classification schemes is in the main lymphoma article.

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.

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.

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.

ATL is usually a highly aggressive non-Hodgkin's lymphoma with no characteristic histologic appearance except for a diffuse pattern and a mature T-cell phenotype. Circulating lymphocytes with an irregular nuclear contour (leukemic cells) are frequently seen. Several lines of evidence suggest that HTLV-1 causes ATL. This evidence includes the frequent isolation of HTLV-1 from patients with this disease and the detection of HTLV-1 proviral genome in ATL leukemic cells. ATL is frequently accompanied by visceral involvement, hypercalcemia, skin lesions, and lytic bone lesions. Bone invasion and osteolysis, features of bone metastases, commonly occur in the setting of advanced solid tumors, such as breast, prostate, and lung cancers, but are less common in hematologic malignancies. However, patients with HTLV-1–induced ATL and multiple myeloma are predisposed to the development of tumor-induced osteolysis and hypercalcemia. One of the striking features of ATL and multiple myeloma induced bone disease is that the bone lesions are predominantly osteolytic with little associated osteoblastic activity. In patients with ATL, elevated serum levels of IL-1, TGFβ, PTHrP, macrophage inflammatory protein (MIP-1α), and receptor activator of nuclear factor-κB ligand (RANKL) have been associated with hypercalcemia. Immunodeficient mice that received implants with leukemic cells from patients with ATL or with HTLV-1–infected lymphocytes developed hypercalcemia and elevated serum levels of PTHrP. Most patients die within one year of diagnosis.

Infection with HTLV-1, like infection with other retroviruses, probably occurs for life and can be inferred when antibody against HTLV-1 is detected in the serum.

One classification system for lymphomas divides the diseases according to the size of the white blood cells that has turned cancerous. The large-cell lymphomas have large cells. A large cell, in this context, has a diameter of 17 to 20 µm. Other groups of lymphomas in this system are the small-cell lymphomas and mixed-cell lymphomas.

Follicular lymphoma is a type of blood cancer. It is the most common of the indolent (slow-growing) non-Hodgkin's lymphomas, and the second-most-common form of non-Hodgkin's lymphomas overall. It is defined as a lymphoma of follicle center B-cells (centrocytes and centroblasts), which has at least a partially follicular pattern. It is positive for the B-cell markers CD10, CD19, CD22, and usually CD20, but almost always negative for CD5.

There are several synonymous and obsolete terms for this disease, such as CB/CC lymphoma (Centroblastic and Centrocytic lymphoma), nodular lymphoma and Brill-Symmers Disease.