## Follicular Lymphoma: Clinical & Pathologic Features **Key Point:** Follicular lymphoma (FL) is the second most common NHL (15–20% of cases), but DLBCL is the most common (30–40%). This distinction is frequently tested. ### Epidemiology & Presentation | Feature | Follicular Lymphoma | DLBCL | |---------|-------------------|-------| | Frequency | 2nd most common (15–20%) | Most common (30–40%) | | Typical age | 55–60 years | 64 years | | Stage at diagnosis | Advanced (III–IV) in 80% | Variable (I–IV) | | Indolence | Yes, slow-growing | No, aggressive | | Median survival | 8–10 years (without Rx) | 5–10 years (with Rx) | **High-Yield:** The question stem says FL is "the most common type of NHL" — this is **FALSE**. DLBCL is the most common. FL is the second most common. ### Cytogenetics: t(14;18) **Key Point:** The t(14;18) translocation is pathognomonic for follicular lymphoma. - **Translocation:** t(14;18)(q32;q21) - **Genes involved:** BCL2 (chromosome 18) and immunoglobulin heavy chain (IgH, chromosome 14) - **Mechanism:** Juxtaposition of BCL2 to the IgH enhancer → constitutive BCL2 overexpression → resistance to apoptosis - **Frequency:** Present in ~90% of follicular lymphomas **Mnemonic:** FL = **F**ollicular, **L**ymphoma, **t(14;18)** = BCL2 ↑ = **B**ad apoptosis (anti-apoptotic) ### Histopathology - **Pattern:** Nodular (follicular) architecture - **Cellular composition:** Small lymphocytes (T cells) surrounding neoplastic B cells - **Germinal center hyperplasia:** Present; the lymphoma arises from germinal center B cells - **Grade:** I–II (low-grade, indolent); Grade III (higher risk of transformation) **Clinical Pearl:** FL is a "germinal center lymphoma" — it originates from the germinal center of secondary lymphoid follicles. ### Clinical Course **Indolent behavior:** - Slow growth, often asymptomatic at diagnosis - Median survival: 8–10 years without treatment - Can transform to DLBCL (Richter transformation) in 3–5% of cases per year - Often presents in advanced stage (III–IV) due to lack of early symptoms **High-Yield:** FL is indolent but incurable with standard therapy. "Watch and wait" is an acceptable initial strategy for asymptomatic patients. ### Why Option 3 is Wrong Option 3 states: "It is the most common type of non-Hodgkin lymphoma and typically presents in advanced stage." - **"Most common"** is FALSE. DLBCL is the most common NHL (30–40%); FL is second (15–20%). - **"Typically presents in advanced stage"** is TRUE (80% present with stage III–IV). Since one part is false, the entire statement is incorrect and is the answer. **Warning:** Do not confuse the two most common NHLs: - **DLBCL:** Most common, aggressive, can present at any stage - **FL:** Second most common, indolent, usually advanced stage at diagnosis [cite:Robbins 10e Ch 13]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.