Non-Hodgkin's Lymphoma

Non-Hodgkin's lymphoma (NHL) is a heterogeneous group of malignant lymphoid neoplasms arising from B-cells, T-cells, or natural killer (NK) cells, presenting with lymphadenopathy, extranodal involvement, and systemic symptoms.

Definition

Non-Hodgkin's lymphoma (NHL) is a heterogeneous group of malignant lymphoid neoplasms arising from B-cells, T-cells, or natural killer (NK) cells, presenting with lymphadenopathy, extranodal involvement, and systemic symptoms.

Epidemiology

Accounts for ~4% of all cancers worldwide
More common in adults; median age ~60 years
Slight male predominance
Incidence increasing due to aging population and immunosuppressive conditions
Higher risk in immunocompromised individuals (HIV, post-transplant, autoimmune disorders)

Etiology

Mostly idiopathic; some cases linked to chronic antigenic stimulation
Genetic abnormalities: translocations, mutations (BCL2, BCL6, MYC, TP53)
Viral infections: EBV (Burkitt lymphoma, some T/NK cell lymphomas), HTLV-1, HCV
Immunodeficiency or immunosuppression
Environmental exposures: pesticides, herbicides, solvents

Pathophysiology

Malignant transformation of B-cells, T-cells, or NK cells
Uncontrolled proliferation and impaired apoptosis
Clonal expansion in lymph nodes and extranodal tissues
Potential bone marrow, spleen, liver, and CNS involvement
Variable aggressiveness: indolent vs. aggressive subtypes
Immune dysfunction can lead to infections and paraneoplastic phenomena