A.16 Non-Hodgkin's Lymphoma Flashcards
A.16 Non-Hodgkin’s Lymphoma
Epidemiology
NHL is the most prevalent hematopoietic neoplasm, accounting for approximately 85% of lymphomas.
Age:
* Overall incidence increases with age, peaking at ≥50 years.
* Subtype variation with age: High-grade lymphomas are more common in children and young adults (ages 20–40 years).
A.16 Non-Hodgkin’s Lymphoma
Etiology
Chromosomal Translocations: Notably, most occur with the translocation t(14;18).
Infectious Agents:EBV, HIV, HTLV-1, Helicobacter pylori associated with gastric lymphoma (e.g., MALT lymphoma, diffuse large B-cell lymphoma).
Autoimmune Disorders: Includes conditions like Hashimoto’s thyroiditis and rheumatic disease.
Immunodeficiency: Linked to congenital immunodeficiencies, AIDS, and history of chemotherapy or hormonal therapy.
Environmental Factors: Exposure to aromatic hydrocarbons (e.g., benzene) and radiation.
A.16 Non-Hodgkin’s Lymphoma
T-Cell Lymphomas
Mycosis Fungoides
* Most prevalent form of cutaneous T-cell lymphoma (CTCL).
* Primarily involves skin.
* Characterized by pruritic cutaneous plaques and patches that may evolve into brownish nodules.
* Can progress to Sézary syndrome (T-cell leukemia).
Sézary Syndrome
* Advanced form of CTCL.
* Manifests as skin involvement and development of circulating T-cell leukemia.
* Can result from the progression of mycosis fungoides:
* Peripheral blood shows CD4+ cells with significant abnormality (termed Sézary cells).
Adult T-Cell Lymphoma
Occurs most frequently in adults.
Associated with HTLV-1 infection.
Presents with:
Hypercalcemia (elevated calcium levels).
Lymphadenopathy (swelling of lymph nodes).
LDH (lactate dehydrogenase) elevation.
Potentially affects multiple organ systems.
T-Cell Lymphoblastic Lymphoma
* Primarily seen in adolescents and young adults (ages 8–21).
* Mediastinal mass may occur, leading to compression of structures such as the heart and superior vena cava syndrome.
A.16 Non-Hodgkin’s Lymphoma
B-Cell Lymphomas (85% of All NHL)
1. Small Lymphocytic Lymphoma (SLL)
* Most common low-grade lymphoma in adults.
* Characterized by a slow-growing, painful course with alternating swellings and waning symptoms.
* Associated with:
* Overexpression of Bcl-2.
* Atypical lymphocytes with a mature appearance.
* Diagnosis often requires lymph node involvement.
2. Chronic Lymphocytic Leukemia (CLL)
* Affects both blood and lymphoid tissue and may involve BRAFV600 mutations.
* Demonstrates a specific immunophenotype (TRAP positive, CD5+, CD10-).
* Common symptoms include lymphadenopathy and splenomegaly.
3. Hairy Cell Leukemia
* Diagnosed by the presence of hairy cells.
* Associated with symptoms like splenomegaly and cytopenias.
* Typically responds well to treatment.
4. Mantle Cell Lymphoma
* More prevalent in older males, particularly in regions like Europe and North America.
* Characterized by t(11;14) translocations leading to cyclin D1 overexpression.
* Frequently aggressive, with a poor prognosis.
5. Burkitt Lymphoma
* More common in children and young adults, especially in equatorial Africa and South America.
* Distinguished by rapid growth and often presents with abdominal masses.
* Associated with EBV infection, especially in endemic forms.
6. Precursor B-Cell Lymphoblastic Lymphoma
* More common among adolescents and young adults.
* Typically presents as an aggressive lymphoma and may lead to bowel obstruction.
A.16 Non-Hodgkin’s Lymphoma
Symptoms in Low-Grade Lymphomas:
- Often insidious onset with vague symptoms.
- Symptoms may include lymphadenopathy, splenomegaly, and bone marrow infiltration.
- Common manifestations: fatigue, weakness, and signs of infection.
A.16 Non-Hodgkin’s Lymphoma
Staging of Lymphomas:
Staging is based on the Ann Arbor classification.
* Stage I: Involvement of a single lymph node region.
* Stage II: Involvement of two or more lymph node regions on the same side of the diaphragm.
* Stage III: Involvement on both sides of the diaphragm.
* Stage IV: Dissemination of disease (e.g., liver, bone marrow).
A.16 Non-Hodgkin’s Lymphoma
Diagnosis of NHL
Diagnosis is made through a combination of clinical history and laboratory tests.
Blood Tests:
* CBC (Complete Blood Count): Checking for anemia and thrombocytopenia.
* LDH (Lactate Dehydrogenase): Elevated levels can indicate aggressive NHL.
Imaging Studies:
* CT and PET scans are essential for staging.
* MRI may be used as needed, especially for CNS involvement.
A.16 Non-Hodgkin’s Lymphoma
Treatment Strategies:
The choice of treatment is based on the type of lymphoma rather than the disease stage itself.
Therapeutic Options by Grade:
Low-grade
Limited Stage: Curative, Radiation therapy.
Advanced Stage: Palliative, Watch and wait, Polychemotherapy.
High-grade
All Stages: Curative, Polychemotherapy (typically R-CHOP: Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, Prednisone).
