Introduction

Non-Hodgkin’s lymphoma (NHL) is a broad group of cancers that comes from the lymphatic system, specifically from lymphocytes, which are a type of white blood cell that is responsible for the human immune defense system. It is one of the most common hematological malignancies worldwide and affects both adults and children, although it is more frequent in older adults. Unlike Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma includes many subtypes that vary in behavior, treatment response, and prognosis. so what are the differences between these two conditions.

Difference Between Hodgkin’s Lymphoma and Non-Hodgkin’s Lymphoma

Lymphoma is a cancer of the lymphatic system. It is broadly divided into Hodgkin’s lymphoma (HL) and Non-Hodgkin’s lymphoma (NHL). Although both arise from lymphocytes, they differ in pathology, spread, symptoms, treatment response, and prognosis.

Quick Comparison Table

Feature	Hodgkin’s Lymphoma	Non-Hodgkin’s Lymphoma
Definition	Malignant lymphoma characterized by presence of Reed-Sternberg cells	Group of lymphoid cancers without Reed-Sternberg cells
Cell of Origin	Usually B lymphocytes	B cells, T cells, or NK cells
Characteristic Cell	Reed-Sternberg giant cells present	Reed-Sternberg cells absent
Age Group	Common in young adults and older adults (bimodal peak)	More common in older adults, but can occur at any age
Pattern of Spread	Spreads in an orderly, contiguous manner from one lymph node group to another	Often spreads unpredictably and non-contiguously
Lymph Node Involvement	Usually starts in cervical or mediastinal nodes	Can start in many lymph node groups
Extranodal Disease	Less common	More common (GIT, skin, brain, bone marrow, etc.)
Number of Types	Fewer subtypes	Many subtypes
Common Symptoms	Painless lymphadenopathy, fever, night sweats, weight loss	Same symptoms plus more extranodal symptoms
Prognosis	Generally very good, high cure rate	Depends on subtype; some curable, some chronic
Treatment	Chemotherapy ± radiotherapy	Chemotherapy, immunotherapy, targeted therapy, radiotherapy
Examples	Nodular sclerosis HL, Mixed cellularity HL	Diffuse large B-cell lymphoma, Follicular lymphoma, Burkitt lymphoma

Detailed Difference

1. Presence of Reed-Sternberg Cells

This is the most important distinction.

• Hodgkin’s lymphoma: Contains large abnormal Reed-Sternberg cells seen on biopsy.
• Non-Hodgkin’s lymphoma: Does not contain Reed-Sternberg cells.

2. Pattern of Spread

• Hodgkin’s lymphoma: Usually spreads from one lymph node region to the next nearby region.
• Non-Hodgkin’s lymphoma: May skip areas and spread widely early.

3. Extranodal Involvement

• Hodgkin’s lymphoma: Mainly remains in lymph nodes.
• Non-Hodgkin’s lymphoma: Frequently affects organs outside lymph nodes such as stomach, intestines, skin, CNS, or marrow.

4. Types of Cells Involved

• Hodgkin’s lymphoma: Mostly B-cell origin.
• Non-Hodgkin’s lymphoma: Can arise from B-cells, T-cells, or NK cells.

5. Prognosis

• Hodgkin’s lymphoma: One of the most curable cancers, especially early stages.
• Non-Hodgkin’s lymphoma: Outcome varies widely depending on subtype and stage.

6. Common Sites

• Hodgkin’s lymphoma: Neck nodes, mediastinum.
• Non-Hodgkin’s lymphoma: Any lymph node group or extranodal tissue.

Memory Trick

Hodgkin’s = Has Reed-Sternberg cells
Non-Hodgkin’s = No Reed-Sternberg cells

Definition

Non-Hodgkin’s lymphoma is a malignant disorder characterized by uncontrolled proliferation of lymphoid cells, mainly B lymphocytes, T lymphocytes, or natural killer (NK) cells, occurring in lymph nodes or extranodal lymphoid tissues. It represents all lymphomas that do not show the classical Reed-Sternberg cells seen in Hodgkin’s lymphoma.

NHL is not a single disease but a collection of many distinct lymphoid malignancies, classified according to the type of cell involved, genetic features, and growth pattern.

Examples include:

• Diffuse large B-cell lymphoma (DLBCL)
• Follicular lymphoma
• Burkitt lymphoma
• Mantle cell lymphoma
• Marginal zone lymphoma
• Peripheral T-cell lymphoma
• Cutaneous T-cell lymphoma

Aetiology (Causes and Risk Factors)

The exact cause of Non-Hodgkin’s lymphoma is not fully understood, but several factors are known to increase the risk.

1. Genetic Mutations

Changes in DNA within lymphocytes can cause abnormal growth and resistance to cell death. These mutations may occur spontaneously or due to environmental exposure.

Examples include:

• t(14;18) translocation in follicular lymphoma
• c-MYC translocation in Burkitt lymphoma
• BCL6 abnormalities in diffuse large B-cell lymphoma

2. Immunodeficiency States

People with weakened immune systems are at higher risk.

Examples:

• HIV/AIDS
• Congenital immunodeficiency disorders
• Post-organ transplant immunosuppression
• Long-term use of immunosuppressive drugs

3. Autoimmune Diseases

Chronic immune stimulation may predispose to lymphoma.

Examples:

• Rheumatoid arthritis
• Sjögren syndrome
• Systemic lupus erythematosus
• Hashimoto thyroiditis

4. Infections

Certain infections are associated with specific lymphoma subtypes.

• Epstein-Barr virus (EBV): Burkitt lymphoma, some aggressive lymphomas
• Helicobacter pylori: Gastric MALT lymphoma
• Hepatitis C virus: Marginal zone lymphoma
• Human T-cell leukemia virus type 1 (HTLV-1): Adult T-cell lymphoma
• Human herpesvirus 8 (HHV-8): Primary effusion lymphoma

5. Environmental and Occupational Exposure

• Pesticides
• Herbicides
• Benzene
• Radiation exposure
• Certain industrial chemicals

6. Age and Gender

• Incidence increases with age
• Slight male predominance in many subtypes

7. Family History

Having a close relative with lymphoma or hematological cancer may slightly increase risk.

Pathophysiolog

Non-Hodgkin’s lymphoma develops when lymphocytes undergo malignant transformation. Normally, lymphocytes grow, mature, perform immune functions, and die in an organized manner. In NHL, mutations disrupt this balance.

Stepwise Mechanism

1. Genetic Damage

DNA mutations or chromosomal translocations occur in B-cells, T-cells, or NK cells.

2. Loss of Growth Control

Mutated cells begin to multiply uncontrollably and evade apoptosis (programmed cell death).

3. Clonal Expansion

The abnormal cell reproduces identical malignant cells, forming a clone.

4. Tissue Infiltration

Cancer cells accumulate in:

• Lymph nodes
• Bone marrow
• Spleen
• Liver
• Gastrointestinal tract
• Skin
• Central nervous system

5. Immune Dysfunction

Normal lymphocyte production is impaired, leading to recurrent infections and reduced immunity.

6. Organ Damage

Large tumor masses or diffuse infiltration interfere with organ function.

Classification

NHL can be broadly divided into:

A. Indolent (Slow Growing)

• Follicular lymphoma
• Small lymphocytic lymphoma
• Marginal zone lymphoma

These may remain stable for years but can relapse repeatedly.

B. Aggressive (Fast Growing)

• Diffuse large B-cell lymphoma
• Mantle cell lymphoma
• Peripheral T-cell lymphoma

Require urgent treatment.

C. Highly Aggressive

• Burkitt lymphoma
• Lymphoblastic lymphoma

Rapid progression but often responsive to intensive therapy.

Signs and Symptoms

Clinical presentation depends on subtype, site, and stage.

1. Lymphadenopathy

Most common feature.

• Enlarged lymph nodes
• Usually painless
• Common in neck, axilla, groin

Nodes may be firm, rubbery, and persistent.

2. Constitutional (B) Symptoms

These suggest systemic disease:

• Unexplained fever
• Drenching night sweats
• Weight loss (>10% body weight in 6 months)

3. Fatigue and Weakness

Due to anemia, cytokine release, or chronic disease.

4. Recurrent Infections

From impaired immune function.

5. Extranodal Symptoms

Gastrointestinal Involvement

• Abdominal pain
• Nausea
• Vomiting
• Bowel obstruction
• GI bleeding

CNS Involvement

• Headache
• Seizures
• Weakness
• Personality changes

Skin Involvement

• Nodules
• Plaques
• Itching

Bone Marrow Involvement

• Pallor
• Easy bruising
• Bleeding
• Infections

6. Hepatosplenomegaly

Enlarged liver or spleen may cause abdominal fullness.

7. Mediastinal Mass

May cause:

• Cough
• Chest pain
• Dyspnea
• Superior vena cava obstruction

Investigations to Do as a Doctor

Proper diagnosis requires a systematic approach.

1. Full Clinical Assessment

• History of symptoms duration
• Weight loss, fever, sweats
• Exposure history
• HIV risk factors
• Autoimmune disease history
• Drug history

2. Physical Examination

• Lymph node regions
• Liver and spleen size
• Skin lesions
• Signs of anemia
• Neurological assessment

Laboratory Investigations

3. Complete Blood Count (CBC)

May reveal:

• Anemia
• Leukopenia
• Leukocytosis
• Thrombocytopenia

4. Peripheral Blood Film

May show abnormal lymphoid cells.

5. ESR / CRP

Markers of inflammation.

6. LDH (Lactate Dehydrogenase)

Often elevated in aggressive disease and high tumor burden.

7. Uric Acid

May be elevated due to rapid cell turnover.

8. Liver Function Tests

Assess liver involvement and chemotherapy readiness.

9. Renal Function Tests

Important before treatment.

10. Viral Screening

• HIV
• Hepatitis B
• Hepatitis C

Tissue Diagnosis

11. Excisional Lymph Node Biopsy

Gold standard investigation.

A whole node is removed for:

• Histology
• Immunohistochemistry
• Flow cytometry
• Cytogenetics

Fine needle aspiration alone is usually insufficient.

12. Bone Marrow Aspiration and Trephine Biopsy

Used for staging and marrow involvement.

Imaging Studies

13. Chest X-ray

Detect mediastinal mass.

14. CT Scan

Neck, chest, abdomen, pelvis for staging.

15. PET-CT Scan

Useful for:

• Disease extent
• Response assessment
• Detecting residual active disease

16. MRI

Used for CNS, spine, or soft tissue involvement.

Special Tests

17. Lumbar Puncture

If CNS involvement suspected.

18. Molecular Studies

Detect genetic abnormalities and guide prognosis.

Staging

Ann Arbor staging system is commonly used:

• Stage I: Single lymph node region or single extranodal site
• Stage II: Two or more lymph node regions on same side of diaphragm
• Stage III: Both sides of diaphragm involved
• Stage IV: Disseminated extranodal disease (bone marrow, liver, CNS)

Suffixes:

• A = no B symptoms
• B = fever, sweats, weight loss

Complications

Non-Hodgkin’s lymphoma can produce many complications.

Disease-Related Complications

1. Bone Marrow Failure

Causing:

• Severe anemia
• Infection
• Bleeding

2. Organ Compression

Tumor masses may compress:

• Airways
• Ureters
• Blood vessels
• Spinal cord

3. CNS Spread

Neurological deficits and seizures.

4. Intestinal Obstruction or Perforation

Especially with abdominal lymphoma.

5. Hypercalcemia

Occasionally seen in some subtypes.

6. Tumor Lysis Syndrome

Rapid destruction of cancer cells causing:

• Hyperuricemia
• Hyperkalemia
• Hyperphosphatemia
• Renal failure

Treatment-Related Complications

7. Neutropenic Sepsis

Medical emergency after chemotherapy.

8. Cardiotoxicity

Some drugs (e.g., doxorubicin) can damage heart.

9. Infertility

Following chemotherapy/radiotherapy.

10. Secondary Malignancies

Long-term risk after treatment.

Management

Treatment depends on:

• Histological subtype
• Stage
• Age
• Performance status
• Organ function
• Presence of symptoms

Management is best coordinated by a hematologist/oncologist.

1. Supportive Care

Essential in all patients.

• Adequate nutrition
• Pain control
• Hydration
• Infection prevention
• Psychological support
• Blood transfusion if needed

2. Watchful Waiting

Used in selected indolent lymphomas without symptoms.

Patients are monitored regularly until treatment becomes necessary.

3. Chemotherapy

Mainstay for many forms of NHL.

Common Regimen: R-CHOP

Used for diffuse large B-cell lymphoma.

Includes:

• Rituximab
• Cyclophosphamide
• Doxorubicin
• Vincristine
• Prednisolone

Other regimens depend on subtype.

4. Immunotherapy

Rituximab

Monoclonal antibody against CD20 on B-cells.

Often combined with chemotherapy.

Other newer antibodies are also available.

5. Targeted Therapy

Used in relapsed or specific subtypes.

Examples:

• Ibrutinib
• Acalabrutinib
• Venetoclax
• Lenalidomide

6. Radiotherapy

Useful for:

• Localized early-stage disease
• Bulky masses
• Palliation of pain or compression

7. Stem Cell Transplant

For relapsed or high-risk disease.

Autologous transplant

Uses patient’s own stem cells.

Allogeneic transplant

Uses donor stem cells.

8. CAR T-Cell Therapy

Advanced treatment for some refractory B-cell lymphomas.

Patient’s T-cells are modified to attack lymphoma cells.

9. Management of Complication

Tumor Lysis Syndrome

• IV fluids
• Allopurinol
• Rasburicase
• Electrolyte correction

Febrile Neutropenia

• Immediate IV antibiotics
• Cultures
• Supportive care

Spinal Cord Compression

• Emergency steroids
• MRI
• Radiotherapy or surgery

Prognosis

Outcome depends on subtype and stage.

Indolent lymphomas may be chronic but manageable for years.

Aggressive lymphomas can often be cured if treated early.

Poor prognostic factors include:

• Advanced age
• High LDH
• Poor performance status
• Advanced stage
• Multiple extranodal sites

The International Prognostic Index (IPI) helps risk stratification.

Prevention

There is no guaranteed prevention, but risk may be reduced by:

• HIV prevention and treatment
• Avoiding unnecessary chemical exposure
• Managing autoimmune diseases
• Treating chronic infections such as H. pylori
• Regular medical review of persistent lymph node swelling

When to Suspect NHL as a Doctor

A doctor should consider Non-Hodgkin’s lymphoma when a patient presents with:

• Persistent painless lymph node enlargement
• Unexplained weight loss
• Night sweats
• Fever of unknown origin
• Hepatosplenomegaly
• Recurrent infections
• Unexplained cytopenias
• Mass lesions in extranodal sites

Prompt biopsy is essential.

Conclusion

Non-Hodgkin’s lymphoma is a diverse group of malignant diseases of the lymphoid system ranging from slow-growing conditions to rapidly fatal cancers if untreated. Because it can mimic infections or benign lymph node enlargement, a high index of suspicion is required in clinical practice. Early diagnosis through biopsy, laboratory tests, and imaging allows timely treatment and significantly improves survival.

Modern therapy now combines chemotherapy, immunotherapy, radiotherapy, targeted drugs, and cellular therapies, making many forms of Non-Hodgkin’s lymphoma highly treatable and in some cases curable. For healthcare professionals, careful assessment, accurate staging, and individualized treatment planning remain the key pillars of management.