Lymphomas

Lymphomas are cancers of the lymphocytes — the very cells your immune system relies on to fight infection. When a single lymphocyte acquires the wrong mutations and begins to divide without restraint, it accumulates in lymph nodes, the spleen, the bone marrow, and sometimes organs far outside the lymphatic system. The result is one of the most fascinating families of malignancy in all of medicine: often curable, wildly diverse in behavior, and a story that stretches from a quiet London pathologist in 1832 to today's engineered T cells.

Understanding lymphoma means learning to think like both a pathologist (what cell went wrong, and what does it look like down the microscope?) and a clinician (how sick is this patient, how far has it spread, and what will cure them?). This page teaches both halves so the classification, staging, and treatment finally make sense together rather than as lists to memorize.

Learning Objectives

• Distinguish Hodgkin lymphoma from non-Hodgkin lymphoma by pathology, spread pattern, and prognosis
• Recognize the Reed-Sternberg cell and understand why it is diagnostic of classical Hodgkin lymphoma
• Apply the Ann Arbor / Lugano staging system and interpret the A/B and bulk modifiers
• Contrast indolent versus aggressive non-Hodgkin lymphomas and how tempo drives treatment
• Outline first-line regimens (ABVD, R-CHOP) and the role of rituximab, radiotherapy, and CAR-T
• Identify common diagnostic and staging pitfalls that trip up students and clinicians

Quick Answer

Lymphoma is a malignant clonal proliferation of lymphocytes. It splits into two great families: Hodgkin lymphoma (HL), defined by the giant Reed-Sternberg cell and by orderly, contiguous spread from one nodal group to the next, and non-Hodgkin lymphoma (NHL), a heterogeneous group of B-cell and T-cell cancers that spread unpredictably. Staging uses the Ann Arbor system (Lugano modification), grading anatomic extent from I to IV with "A" (no symptoms) or "B" (fever, drenching night sweats, weight loss) suffixes. HL is highly curable — often over 85 percent even when advanced — with combination chemotherapy such as ABVD. NHL treatment depends on subtype: indolent lymphomas (e.g., follicular) are managed but rarely cured, while aggressive ones (e.g., diffuse large B-cell lymphoma) are treated aggressively and often cured with R-CHOP. Diagnosis always requires a tissue biopsy — never a needle aspirate alone.

Where It Came From

In 1832, Thomas Hodgkin, a Quaker pathologist at Guy's Hospital in London, published On Some Morbid Appearances of the Absorbent Glands and Spleen. He described seven patients with progressive, painless enlargement of the lymph glands and spleen that was not caused by infection or a distant primary tumor — a genuinely new disease entity. The paper was largely ignored during his lifetime. Hodgkin, more interested in reform and philanthropy than self-promotion, never had a microscope good enough to see the cells that define the disease. The need that drove his work was simple but profound: physicians of the era lumped all glandular swelling together as "scrofula" or infection, and Hodgkin insisted that careful anatomic observation could separate distinct diseases — the founding logic of pathology itself.

The condition bore no name until Samuel Wilks rediscovered Hodgkin's cases in the 1860s, added his own, and generously named the disease after its describer. The characteristic giant cell was finally identified by Carl Sternberg (1898) and Dorothy Reed (1902), giving us the Reed-Sternberg cell. For a century, Hodgkin lymphoma was a near-uniform death sentence. The turning point came in the mid-20th century: Henry Kaplan pioneered high-dose, precisely targeted radiotherapy in the 1960s, and Vincent DeVita at the NCI developed the MOPP combination chemotherapy regimen in 1964–1970, proving for the first time that a disseminated solid cancer could be cured with drugs. That success reshaped oncology's entire ambition — from palliation toward cure. Non-Hodgkin lymphomas, meanwhile, were only rationally classified once immunophenotyping and molecular tools (from the 1980s onward, culminating in the WHO classification) revealed them to be dozens of distinct diseases of B, T, and NK cells.

Hodgkin Lymphoma: The Reed-Sternberg Cell and Orderly Spread

The defining feature of classical Hodgkin lymphoma is the Reed-Sternberg (RS) cell: a large cell, often binucleate with two mirror-image nuclei each containing a prominent eosinophilic nucleolus — the classic "owl-eye" appearance. Remarkably, RS cells are a minority of the tumor; the bulk of the enlarged node is a reactive infiltrate of lymphocytes, eosinophils, and plasma cells that the RS cells recruit. RS cells are derived from germinal-center B cells that have lost most of their B-cell identity, and they characteristically express CD15 and CD30 but are usually CD20 negative — an immunophenotype worth memorizing because it is frequently examined.

Classical HL has four subtypes, of which nodular sclerosis is the most common (especially in young women, often presenting with a mediastinal mass). A separate entity, nodular lymphocyte-predominant HL, behaves more like an indolent B-cell NHL, features "popcorn" (LP) cells that are CD20 positive, and is treated differently.

Clinically, HL shows a bimodal age distribution (peaks in the 20s and again after 55) and spreads in an orderly, contiguous fashion from one nodal region to the next — a behavior so predictable that it historically justified staging laparotomy. Painless cervical or supraclavicular lymphadenopathy is the classic presentation. A textbook clue is Pel-Ebstein fever (cyclical fever) and the curious symptom of alcohol-induced nodal pain. Epstein-Barr virus is found in the RS cells of a substantial fraction of cases and is implicated in pathogenesis.

Non-Hodgkin Lymphoma: A Family of Many Diseases

NHL is not one disease but roughly 60 entities in the WHO classification. Around 85–90 percent are of B-cell origin. The single most useful clinical axis is tempo:

• Indolent (low-grade) lymphomas grow slowly, present with widespread but asymptomatic disease, respond to treatment, relapse repeatedly, and are generally incurable but very survivable over many years. The prototype is follicular lymphoma, driven by the t(14;18) translocation that overexpresses the anti-apoptotic protein BCL-2. Others include marginal zone lymphoma (including MALT lymphoma, classically gastric and linked to Helicobacter pylori) and small lymphocytic lymphoma (the tissue counterpart of CLL).
• Aggressive (high-grade) lymphomas grow fast and are rapidly fatal untreated — but are often curable. The prototype is diffuse large B-cell lymphoma (DLBCL), the most common NHL overall.
• Very aggressive lymphomas such as Burkitt lymphoma, driven by MYC translocation t(8;14), have among the fastest doubling times of any human tumor and can present as an oncologic emergency with tumor lysis syndrome.

A paradox worth remembering: aggressive lymphomas are more curable than indolent ones, because rapidly dividing cells are exquisitely sensitive to chemotherapy, whereas slow-growing cells largely escape it. NHL spreads unpredictably (non-contiguous), more often involves extranodal sites and bone marrow, and is more likely than HL to present at an advanced stage.

Staging: The Ann Arbor and Lugano Systems

Staging answers "how far has it spread?" and directly guides treatment intensity. The Ann Arbor system, refined by the Lugano classification, defines four stages:

Stage	Extent
I	One lymph node region (or one extranodal site)
II	Two or more regions on the same side of the diaphragm
III	Regions on both sides of the diaphragm
IV	Diffuse involvement of extralymphatic organs (e.g., bone marrow, liver, lung)

Two modifiers matter enormously:

• A vs B: "B symptoms" are unexplained fever above 38 degrees C, drenching night sweats, and weight loss of more than 10 percent of body weight over six months. Their presence (stage "B") worsens prognosis and often escalates therapy.
• X (bulky disease): a large tumor mass (classically a mediastinal mass wider than one-third of the thoracic diameter) that may warrant added radiotherapy.

Modern staging relies on PET-CT, which is far more sensitive than CT alone and also allows interim response assessment using the Deauville 5-point scale. Bone marrow biopsy is still used in selected cases, though PET has reduced its necessity in HL.

Worked example. A 26-year-old woman has a right supraclavicular node and a mediastinal mass on one side of the diaphragm, with three months of drenching night sweats and 8 kg weight loss. Biopsy shows nodular sclerosis HL with CD15+/CD30+ RS cells. The mediastinal mass exceeds one-third of the thoracic width. Her stage is II-B, bulky (X) — two regions, same side of the diaphragm, B symptoms present, bulky disease — which typically means combination chemotherapy (ABVD) followed by consolidative radiotherapy to the bulky site.

Treatment: From Combination Chemotherapy to Engineered Cells

Hodgkin lymphoma. The backbone is ABVD (Adriamycin/doxorubicin, Bleomycin, Vinblastine, Dacarbazine). Early-stage disease may need only a few cycles plus involved-site radiotherapy; advanced disease needs more cycles, often guided by interim PET (escalating to the more intensive escalated-BEACOPP or adding brentuximab vedotin if PET-positive). Cure rates exceed 85–90 percent. Because most patients are young and cured, late toxicity dominates survivorship: bleomycin lung injury, anthracycline cardiomyopathy, secondary leukemias and solid cancers (especially breast cancer after chest radiotherapy), and infertility. Relapsed HL is treated with brentuximab vedotin (anti-CD30) and checkpoint inhibitors (nivolumab, pembrolizumab), which are strikingly effective because RS cells overexpress PD-L1.

Non-Hodgkin lymphoma. Treatment is subtype- and tempo-driven:

• Aggressive B-cell (DLBCL): R-CHOP — Rituximab plus Cyclophosphamide, Hydroxydaunorubicin (doxorubicin), Oncovin (vincristine), and Prednisone — given every 21 days for about six cycles, cures roughly 60–70 percent. The addition of rituximab, an anti-CD20 monoclonal antibody, in the early 2000s was one of the most important advances in oncology, adding around 10–15 percentage points to cure rates.
• Indolent (follicular): early asymptomatic disease is often watched ("watch and wait"); symptomatic disease is treated with rituximab-based chemoimmunotherapy, but the goal is control, not cure.
• Relapsed/refractory aggressive NHL: high-dose chemotherapy with autologous stem cell transplant, and increasingly CAR-T cell therapy — the patient's own T cells engineered to target CD19 — which can cure patients who have failed everything else.

Supportive care is critical: tumor lysis syndrome prophylaxis (hydration, allopurinol or rasburicase) is mandatory in bulky, fast-growing disease like Burkitt, and CNS prophylaxis is considered in high-risk DLBCL and Burkitt lymphoma.

Real-World Applications

• Primary care recognition: persistent, painless, rubbery lymphadenopathy for more than 2–4 weeks — especially supraclavicular nodes, or nodes with B symptoms — warrants urgent referral and excisional biopsy, not reassurance.
• Gastroenterology: eradicating H. pylori can cause regression of early gastric MALT lymphoma — a rare instance of curing a cancer with antibiotics.
• Survivorship clinics: cured young HL patients need lifelong screening for secondary breast cancer, cardiac disease, and thyroid dysfunction — the cure creates a new set of clinical needs.
• Oncologic emergencies: a young patient with a rapidly enlarging abdominal mass, high LDH, and metabolic derangement may have Burkitt lymphoma with tumor lysis — a same-day admission.

Common Mistakes

1. Diagnosing lymphoma on a fine-needle aspirate. FNA gives cells but destroys architecture, and architecture (follicular vs diffuse, nodal effacement) is essential for classification. Correction: obtain an excisional or core biopsy with enough tissue for immunophenotyping and molecular studies.
2. Assuming aggressive means incurable and indolent means benign. It is the reverse of intuition: aggressive DLBCL is frequently cured, while indolent follicular lymphoma is chronic and generally not cured. Correction: let tempo guide expectations, and remember that fast-dividing tumors are chemo-sensitive.
3. Confusing Reed-Sternberg cells with diagnosis by themselves. RS-like cells can appear in infectious mononucleosis and some carcinomas. Correction: diagnosis requires RS cells in the appropriate reactive background with the CD15+/CD30+/CD20- immunophenotype.
4. Forgetting that "B" refers to symptoms, not stage number. Students write "stage 2" and omit A/B and bulk. Correction: always report the full descriptor (e.g., II-B-X), because it changes treatment.

Comparison and Connections

Feature	Hodgkin Lymphoma	Non-Hodgkin Lymphoma
Defining cell	Reed-Sternberg (CD15+/CD30+)	Varies by subtype (mostly B-cell)
Spread	Orderly, contiguous	Unpredictable, non-contiguous
Extranodal / marrow	Uncommon	Common
Stage at presentation	Often localized	Often advanced
Age pattern	Bimodal (20s and older adults)	Rises with age
Curability	Very high (85%+)	Depends on subtype
B symptoms	Prognostically important	Common in aggressive types

Lymphoma also connects to leukemia: CLL and small lymphocytic lymphoma are the same disease in blood vs node, and lymphoblastic lymphoma overlaps with acute lymphoblastic leukemia. See related pages in Hematology, and the immune biology underpinning lymphocyte development in Immunology.

Practice Questions

Recall

Q: What is the immunophenotype of the Reed-Sternberg cell in classical Hodgkin lymphoma? A: CD15 positive and CD30 positive, typically CD20 negative.

Understanding

Q: Why are indolent lymphomas generally harder to cure than aggressive ones? A: Chemotherapy and radiotherapy preferentially kill rapidly dividing cells. Indolent lymphoma cells cycle slowly, so most escape cytotoxic therapy, allowing repeated relapse; aggressive lymphoma cells divide fast and are therefore highly sensitive to treatment, making cure possible.

Application

Q: A 40-year-old man has enlarged nodes in the neck and both axillae plus the inguinal region, with drenching night sweats and marrow involvement on biopsy. What is his Ann Arbor stage? A: Marrow (an extralymphatic organ) is involved, which alone makes this stage IV-B (B for the night sweats), regardless of nodal distribution.

Analysis

Q: A cured 30-year-old woman who received chest radiotherapy for nodular sclerosis HL returns 15 years later. What long-term risks must her follow-up specifically address, and why? A: Secondary breast cancer (radiation to breast tissue at a young age), cardiovascular disease and valvular damage (mediastinal radiation plus anthracycline), hypothyroidism (neck radiation), and secondary leukemia. The very treatments that cured her created these delayed risks, so survivorship screening is a distinct and lifelong clinical need.

FAQ

Is lymphoma curable? Often, yes. Hodgkin lymphoma is one of the most curable cancers (over 85 percent even in advanced stages). Aggressive NHL like DLBCL is cured in the majority. Indolent NHL is usually controlled long-term rather than cured.

What is the difference between lymphoma and leukemia? Both are cancers of blood cells, but lymphoma predominantly forms solid masses in lymph nodes and lymphoid tissue, while leukemia predominantly circulates in the blood and marrow. Some diseases (e.g., CLL/SLL) straddle both.

Why can't a needle biopsy diagnose lymphoma? Accurate classification needs the tissue architecture and enough cells for immunophenotyping and molecular tests. A fine-needle aspirate collects loose cells and loses the structural pattern, so an excisional or generous core biopsy is preferred.

What are B symptoms and why do they matter? Fever, drenching night sweats, and unexplained weight loss over 10 percent. They signify more active disease, worsen prognosis, and often mean more intensive treatment — they upgrade the stage descriptor from A to B.

What is CAR-T therapy? Chimeric antigen receptor T-cell therapy re-engineers a patient's own T cells to recognize a lymphoma marker (usually CD19) and attack the cancer. It can cure some patients with relapsed aggressive B-cell lymphoma who have exhausted standard options.

Quick Revision

• HL = Reed-Sternberg cell (CD15+/CD30+/CD20-), orderly contiguous spread, bimodal age, highly curable with ABVD.
• NHL = ~60 diseases, mostly B-cell, unpredictable spread; tempo (indolent vs aggressive) drives management.
• DLBCL (aggressive, most common NHL) is often cured with R-CHOP; follicular (indolent, t(14;18)/BCL-2) is controlled, not cured.
• Ann Arbor / Lugano I–IV, with A/B (symptoms) and X (bulk) modifiers; stage with PET-CT.
• Always excisional/core biopsy, never FNA alone.
• Rituximab (anti-CD20), brentuximab (anti-CD30), checkpoint inhibitors, and CAR-T are the modern immunotherapy toolkit.
• Cured young patients need lifelong survivorship care for late toxicities.

Related Topics

Prerequisites

• Hematology overview
• Immunology — lymphocyte development and immune surveillance

Related Topics

• Leukemias — the circulating counterpart of lymphoid malignancy
• Oncology — general principles of cancer staging and chemotherapy

Next Topics

• Multiple myeloma and plasma cell disorders
• Hematopoietic stem cell transplantation and CAR-T cell therapy