Follicular and Mantle Cell Lymphoma
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Direct answer
Follicular lymphoma and mantle cell lymphoma are B-cell non-Hodgkin lymphomas separated by their translocations: t(14;18) with BCL2 overexpression in follicular lymphoma, and t(11;14) with cyclin D1 overexpression in mantle cell lymphoma. Follicular lymphoma usually runs an indolent course with painless lymphadenopathy, whereas mantle cell lymphoma tends to behave more aggressively. Correct classification shapes the choice between observation and early therapy.
What you must remember
- Follicular translocation: t(14;18)(q32;q21) places BCL2 beside the immunoglobulin heavy chain locus, and BCL2 overexpression blocks apoptosis.
- Follicular immunophenotype: CD10 positive and CD20 positive, with CD5 usually negative.
- Grading: follicular lymphoma is graded 1 to 3 by centroblast count, and grade 3B behaves more like diffuse large B-cell lymphoma.
- Mantle translocation: t(11;14)(q13;q32) drives cyclin D1 overexpression, and SOX11 positivity supports the diagnosis.
- Mantle immunophenotype: CD5 positive, with CD10 and CD23 negative, which separates it from most follicular cases.
- Course: follicular lymphoma is indolent with relapses, while mantle cell lymphoma is more aggressive and often involves the gut.
- Gut disease: lymphomatous polyposis of the intestine is a characteristic feature of mantle cell lymphoma.
- Prognosis: the FLIPI stratifies follicular lymphoma, using age, stage, haemoglobin, nodal sites and lactate dehydrogenase.
Where the exam tries to catch you
Most lost marks come from treating painless lymphadenopathy as one disease, or from misreading the word indolent.
- Trap: Diagnosing follicular lymphoma from any painless nodes in an older adult. Correct: CD5 positivity with cyclin D1 points to mantle cell lymphoma, which runs a more aggressive course.
- Trap: Believing indolent means curable. Correct: Follicular lymphoma is generally not curable with conventional therapy, and relapses are the expected pattern.
- Trap: Using BCL2 as the marker of mantle cell lymphoma. Correct: BCL2 overexpression is the hallmark of follicular lymphoma, while mantle cell lymphoma is defined by cyclin D1.
- Trap: Assuming all low-grade follicular lymphoma needs immediate therapy. Correct: Asymptomatic, low-burden disease is often observed, and therapy is reserved for symptoms or high tumour burden.
Frequently asked questions
Which translocation is characteristic of follicular lymphoma?
Follicular lymphoma is characterised by the t(14;18)(q32;q21) translocation, which places BCL2 beside the immunoglobulin heavy chain locus. BCL2 overexpression blocks apoptosis, allowing the B-cell clone to accumulate over time.
How does mantle cell lymphoma differ from follicular lymphoma on immunophenotype?
Mantle cell lymphoma is CD5 positive and CD10 negative, with nuclear cyclin D1 overexpression from t(11;14). Follicular lymphoma is CD10 positive and usually CD5 negative, which separates the two in most cases.
What is the typical course of follicular lymphoma?
Follicular lymphoma usually follows an indolent course with painless lymphadenopathy that can persist for years. Transformation to diffuse large B-cell lymphoma is the key adverse event and needs prompt reassessment.
Why is mantle cell lymphoma considered more aggressive than follicular lymphoma?
Mantle cell lymphoma generally behaves more aggressively than follicular lymphoma, with frequent extranodal and gastrointestinal involvement and a shorter course. Lymphomatous polyposis of the gut is a characteristic finding in many patients.
Which prognostic index is used for follicular lymphoma?
The Follicular Lymphoma International Prognostic Index (FLIPI) stratifies risk in follicular lymphoma. It combines age, stage, haemoglobin, number of nodal sites and serum lactate dehydrogenase to guide treatment decisions.