Definition/General

Introduction:
-Mantle cell lymphoma (MCL) is a distinct B-cell neoplasm characterized by cyclin D1 overexpression
-It accounts for 3-10% of all non-Hodgkin lymphomas
-MCL shows aggressive clinical behavior with poor overall survival
-It is derived from naive B-cells in the mantle zone.
Origin:
-Arises from mantle zone B-cells surrounding germinal centers
-These cells are unmutated and express IgM/IgD
-MCL cells retain naive B-cell phenotype
-t(11;14)(q13;q32) translocation is characteristic
-Results in CCND1-IGH fusion.
Classification:
-Classified under mature B-cell neoplasms (WHO 2016)
-Nodal type (classical)
-Leukemic non-nodal type
-In situ mantle cell neoplasia
-Indolent MCL
-Pleomorphic variant
-Blastoid variant.
Epidemiology:
-Median age 60-65 years
-Male predominance (3-4:1)
-Rare in children and young adults
-Higher incidence in Western countries
-Represents 6% of all lymphomas
-Incidence increasing with improved recognition.

Clinical Features

Presentation:
-Generalized lymphadenopathy (80-90%)
-Splenomegaly (50-60%)
-Hepatomegaly (25-30%)
-Extranodal involvement (GI tract, bone marrow)
-Waldeyer ring involvement
-CNS involvement (rare).
Symptoms:
-B-symptoms (fever, night sweats, weight loss)
-Fatigue and weakness
-Abdominal discomfort (splenomegaly)
-GI symptoms (nausea, diarrhea)
-Bleeding (thrombocytopenia)
-Recurrent infections.

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Gross Description

Microscopic Description

Immunohistochemistry

Positive Markers:
-CD20 (positive)
-PAX5 (positive)
-Cyclin D1 (positive - diagnostic)
-SOX11 (positive)
-CD79a (positive)
-IgM (positive)
-IgD (positive).
Negative Markers:
-CD23 (negative - distinguishes from CLL)
-CD10 (negative)
-BCL6 (negative)
-CD21 (negative)
-CD35 (negative)
-TdT (negative).
Diagnostic Utility:
-Cyclin D1 is pathognomonic
-SOX11 helps in cyclin D1-negative cases
-CD23 negativity distinguishes from CLL/SLL
-CD10/BCL6 negativity excludes follicular lymphoma.

Molecular/Genetic

Differential Diagnosis

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Specimen Information

[specimen type], [location], measuring [size] cm

Architecture

Shows [diffuse/nodular] pattern with [complete/partial] effacement

Morphology

[Small/medium] sized lymphoid cells with [nuclear features]

Morphological Variant

[Classical/pleomorphic/blastoid] variant

Immunohistochemistry

CD20: [+], Cyclin D1: [+], CD23: [-], SOX11: [+/-]

Proliferation Index

Ki-67: [X]% (proliferation index)

Molecular Studies

t(11;14): [positive/negative], CCND1 rearrangement: [present/absent]

Staging

Stage: [I/II/III/IV], bone marrow: [involved/uninvolved]

Prognostic Factors

MIPI score: [low/intermediate/high], Ki-67: [X]%

Final Diagnosis

Final diagnosis: Mantle cell lymphoma, [variant], Stage [X]